Project description:Macrophages play integral roles in maintaining homeostasis and function in their tissues of residence. In the skin, prenatally seeded and highly specialized macrophages physically interact with sensory nerves and contribute to their regeneration after injury. However, mechanisms underlying the development and maintenance of this paradigmatic, potentially lifelong commitment of macrophages to nociceptors remain largely elusive. Here, we found that infiltrating myeloid progenitor cells approached the sprouting axons of sensory nerves and gradually adopted a nerve-associated macrophage-like profile. This change in identity was steered and maintained by the immediate microenvironment, in particular TGF-β, which was produced by neurons and locally activated by the physical interaction with nerves and integrin-mediated cleavage. Following injury, TGF-β driven specification of macrophages essentially supported nerve regeneration. Overall, we identified TGF-β as a central mediator governing local imprinting and long-term specialization of macrophages in the skin, providing insights into the bidirectional communication between macrophages and sensory nerves.
Project description:Macrophages play integral roles in maintaining homeostasis and function in their tissues of residence. In the skin, prenatally seeded and highly specialized macrophages physically interact with sensory nerves and contribute to their regeneration after injury. However, mechanisms underlying the development and maintenance of this paradigmatic, potentially lifelong commitment of macrophages to nociceptors remain largely elusive. Here, we found that infiltrating myeloid progenitor cells approached the sprouting axons of sensory nerves and gradually adopted a nerve-associated macrophage-like profile. This change in identity was steered and maintained by the immediate microenvironment, in particular TGF-β, which was produced by neurons and locally activated by the physical interaction with nerves and integrin-mediated cleavage. Following injury, TGF-β driven specification of macrophages essentially supported nerve regeneration. Overall, we identified TGF-β as a central mediator governing local imprinting and long-term specialization of macrophages in the skin, providing insights into the bidirectional communication between macrophages and sensory nerves.
Project description:β Cell apoptosis and dedifferentiation are 2 hotly debated mechanisms underlying β cell loss in type 2 diabetes; however, the molecular drivers underlying such events remain largely unclear. Here, we performed a side-by-side comparison of mice carrying β cell-specific deletion of ER-associated degradation (ERAD) and autophagy. We reported that, while autophagy was necessary for β cell survival, the highly conserved Sel1L-Hrd1 ERAD protein complex was required for the maintenance of β cell maturation and identity. Using single-cell RNA-Seq, we demonstrated that Sel1L deficiency was not associated with β cell loss, but rather loss of β cell identity. Sel1L-Hrd1 ERAD controlled β cell identity via TGF-β signaling, in part by mediating the degradation of TGF-β receptor 1. Inhibition of TGF-β signaling in Sel1L-deficient β cells augmented the expression of β cell maturation markers and increased the total insulin content. Our data revealed distinct pathogenic effects of 2 major proteolytic pathways in β cells, providing a framework for therapies targeting distinct mechanisms of protein quality control.
Project description:Macrophages, mainly divided into M1 pro-inflammatory and M2 anti-inflammatory types, play a key role in the transition from inflammation to repair after trauma. In chronic inflammation, such as diabetes and complex bone injury, or the process of certain inflammatory specific emergencies, the ratio of M1/M2 cell populations is imbalanced so that M1-macrophages cannot be converted into M2 macrophages in time, resulting in delayed trauma repair. Early and timely transformation of macrophages from the pro-inflammatory M1-type into the pro-reparative M2-type is an effective strategy to guide trauma repair and establish the original homeostasis. We prepared purified nano-platelet vesicles (NPVs) and assessed their effects on macrophage phenotype switching through transcriptome analysis. The results elucidate that NPVs promote pathways related to angiogenesis, collagen synthesis, cell adhesion, and migration in macrophages, and we speculate that these advantages may promote healing in traumatic diseases.
