ABSTRACT
Osteoarthritis (OA) is an age-related or post-traumatic degenerative whole joint disease characterized by the rupture of articular cartilage homeostasis, the regulatory mechanisms of which remain elusive. This study identifies the essential role of heterogeneous nuclear ribonucleoprotein K (hnRNPK) in maintaining articular cartilage homeostasis. Hnrnpk expression is markedly downregulated in human and mice OA cartilage. The deletion of Hnrnpk effectively accelerates the development of post-traumatic and age-dependent OA in mice. Mechanistically, the KH1 and KH2 domain of Hnrnpk bind and degrade the mRNA of WWC1. Hnrnpk deletion increases WWC1 expression, which in turn leads to the activation of Hippo signaling and ultimately aggravates OA. In particular, intra-articular injection of LPA and adeno-associated virus serotype 5 expressing WWC1 RNA interference ameliorates cartilage degeneration induced by Hnrnpk deletion, and intra-articular injection of adeno-associated virus serotype 5 expressing Hnrnpk protects against OA. Collectively, this study reveals the critical roles of Hnrnpk in inhibiting OA development through WWC1-dependent downregulation of Hippo signaling in chondrocytes and defines a potential target for the prevention and treatment of OA.
Subject(s)
Cartilage, Articular , Chondrocytes , Heterogeneous-Nuclear Ribonucleoprotein K , Hippo Signaling Pathway , Osteoarthritis , Protein Serine-Threonine Kinases , Signal Transduction , Animals , Humans , Male , Mice , Cartilage, Articular/metabolism , Cartilage, Articular/pathology , Chondrocytes/metabolism , Dependovirus/genetics , Disease Models, Animal , Gene Expression Regulation , Heterogeneous-Nuclear Ribonucleoprotein K/metabolism , Heterogeneous-Nuclear Ribonucleoprotein K/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Osteoarthritis/metabolism , Osteoarthritis/genetics , Osteoarthritis/etiology , Osteoarthritis/pathology , Osteoarthritis/therapy , Protein Serine-Threonine Kinases/metabolism , Protein Serine-Threonine Kinases/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolismABSTRACT
The intervertebral disc (IVD) acts as a fibrocartilaginous joint to anchor adjacent vertebrae. Although several studies have demonstrated the cellular heterogeneity of adult mature IVDs, a single-cell transcriptomic atlas mapping early IVD formation is still lacking. Here, the authors generate a spatiotemporal and single cell-based transcriptomic atlas of human IVD formation at the embryonic stage and a comparative mouse transcript landscape. They identify two novel human notochord (NC)/nucleus pulposus (NP) clusters, SRY-box transcription factor 10 (SOX10)+ and cathepsin K (CTSK)+ , that are distributed in the early and late stages of IVD formation and they are validated by lineage tracing experiments in mice. Matrisome NC/NP clusters, T-box transcription factor T (TBXT)+ and CTSK+ , are responsible for the extracellular matrix homeostasis. The IVD atlas suggests that a subcluster of the vertebral chondrocyte subcluster might give rise to an inner annulus fibrosus of chondrogenic origin, while the fibroblastic outer annulus fibrosus preferentially expresseds transgelin and fibromodulin . Through analyzing intercellular crosstalk, the authors further find that notochordal secreted phosphoprotein 1 (SPP1) is a novel cue in the IVD microenvironment, and it is associated with IVD development and degeneration. In conclusion, the single-cell transcriptomic atlas will be leveraged to develop preventative and regenerative strategies for IVD degeneration.
Subject(s)
Intervertebral Disc Degeneration , Intervertebral Disc , Nucleus Pulposus , Humans , Mice , Animals , Cell Differentiation , Transcription FactorsABSTRACT
Brachial plexus root avulsion (BPRA) is one of the most serious injuries of the upper extremity, which requires more effective treatment. Trehalose, a natural disaccharide, has reported to has a protective effect in neurodegenerative diseases. However, the effective effects and mechanism of trehalose on BPRA are still unclear. BPRA rat model were established, and then effects of trehalose on BPRA were investigated. TBHP-treated NSC34 cells with or without trehalose treatment were used for mechanism studies by Western blotting, Immunofluorescence and Flow cytometry analysis. Trehalose elevated the survival of motor neurons in rats after BPRA, suggesting a protective role of trehlose on BPRA. Trehalose treatment in rats after BPRA enhanced the autophage and thus inhibited apoptosis compared with rats in Vehicle group. Moreover, in TBHP-treated NSC34 cells, trehalose promoted the expression of autophage-related markers (LC3 and Beclin-1), concomitant with decreased levels of apoptosis. In vitro mechanism study indicated that the regulations of trehalose on autophage and apoptosis were via the AMPK-ULK1 pathway. Trehalose protects injured MNs by enhancing autophage and inhibiting apoptosis, which demonstrating the essential role of trehalose in the prevention and treatment of BPRA.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Apoptosis/drug effects , Autophagy/drug effects , Brachial Plexus/drug effects , Motor Neurons/drug effects , Protective Agents/pharmacology , Trehalose/pharmacology , Animals , Beclin-1/metabolism , Brachial Plexus/metabolism , Cells, Cultured , Male , Mice , Mice, Inbred C57BL , Motor Neurons/metabolism , Rats , Signal Transduction/drug effects , Spinal Cord/drug effects , Spinal Cord/metabolismABSTRACT
BACKGROUND: Lymphedema is a chronic disease results from impaired flow of the lymphatic system. Therefore, reconstruction of lymphatic system is crucial to treat limb lymphedema. Vascular endothelial growth factor (VEGFC) has been reported to be an important regulator involved in the growth and differentiation of lymphatic endothelial cells; however; the application of exosomes with VEGFC in the treatment of lymphedema has been rarely reported. METHODS: From the membrane-based fusion technology, we constructed engineered exosomes that overexpress CD63-VEGFC fusion protein (CD63-VEGFC/exos). We examined the in vitro effects of CD63-VEGFC/exos on the proliferation, migration, and tube formation of human dermal lymphatic endothelial cells (HDLECs) by MTT assay, migration assay, and tube formation assay, respectively. CD63-VEGFC/exos were embedded in sodium alginate hydrogel and their effect on lymphedema was evaluated by a mouse model. RESULTS: VEGFC could be successfully delivered to lymphatic endothelial cells via engineered CD63-VEGFC/exos. Treatment with CD63-VEGFC/exos resulted in a significant increase in the proliferation, migration, and tube formation of lymphatic endothelial cells. Using CD63-VEGFC/egos in sodium alginate hydrogel enabled a sequenced release of exosomes and markedly improved lymphedema in a mouse model. CONCLUSIONS: Our findings supply a novel adipose tissue-derived stem cell (ADSC)-exo-based strategy that delivers target proteins to lymphatic endothelial cells and thus enhances the treatment of lymphedema.
