Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease that is characterised by aberrant proliferation of activated myofibroblasts and pathological remodelling of the extracellular matrix. Previous studies have revealed that the intermediate filament protein Nestin plays key roles in tissue regeneration and wound healing in different organs. Whether Nestin plays a critical role in the pathogenesis of IPF needs to be clarified.Nestin expression in lung tissues from bleomycin-treated mice and IPF patients was determined. Transfection with Nestin shRNA vectors in vitro that regulated TGF-β/Smad signalling was conducted. Biotinylation assays to observe plasma membrane TβRI, TβRI endocytosis and TβRI recycling after Nestin knockdown were performed. Adeno-associated virus serotype 6 (AAV6)-mediated Nestin knockdown was assessed in vivo.We found that Nestin expression was increased in a murine pulmonary fibrosis model and IPF patients, and that the upregulated protein primarily localised in lung α-SMA+ myofibroblasts. Mechanistically, we determined that Nestin knockdown inhibited TGF-β signalling by suppressing recycling of TβRI to the cell surface and that Rab11 was required for the ability of Nestin to promote TβRI recycling. In vivo, we found that intratracheal administration of adeno-associated virus serotype 6 (AAV6)-mediated Nestin knockdown significantly alleviated pulmonary fibrosis in multiple experimental mice models.In conclusion, our findings reveal a pro-fibrotic function of Nestin partially through facilitating Rab11-dependent recycling of TβRI and shed new light on pulmonary fibrosis treatment.

Background Cancer cachexia is a wasting syndrome that is quite common in terminal-stage cancer patients. Cancer-related anemia is one of the main features of cancer cachexia and mostly results in a poor prognosis. The disadvantages of the current therapies are obvious, but few new treatments have been developed because the pathological mechanism remains unclear. Methods C57BL/6 mice were subcutaneously injected with Lewis lung carcinoma cells to generate a cancer-related anemia model. The treated group received daily intraperitoneal injections of SB505124. Blood parameters were determined with a routine blood counting analyzer. Erythroid cells and hematopoietic stem/progenitor cells were analyzed by flow cytometry. The microarchitecture changes of the femurs were determined by micro-computed tomography scans. Smad2/3 phosphorylation was analyzed by immunofluorescence and Western blotting. The changes in the hematopoietic stem cell niche were revealed by qPCR analysis of both fibrosis-related genes and hematopoietic genes, fibroblastic colony-forming unit assays, and lineage differentiation of mesenchymal stromal cells. Results The mouse model exhibited hematopoietic suppression, marked by a decrease of erythrocytes in the peripheral blood, as well as an increase of immature erythroblasts and reduced differentiation of multipotent progenitors in the bone marrow. The ratio of bone volume/total volume, trabecular number, and cortical wall thickness all appeared to decrease, and the increased osteoclast number has led to the release of latent TGFβ and TGFβ signaling over-activation. Excessive TGFβ deteriorated the hematopoietic stem cell niche, inducing fibrosis of the bone marrow as well as the transition of mesenchymal stromal cells. Treatment with SB505124, a small-molecule inhibitor of TGFβ signaling, significantly attenuated the symptoms of cancer-related anemia in this model, as evidenced by the increase of erythrocytes in the peripheral blood and the normalized proportion of erythroblast cell clusters. Meanwhile, hindered hematopoiesis and deteriorated hematopoietic stem cell niche were also shown to be restored with SB505124 treatment. Conclusion This study investigated the role of TGFβ released by bone remodeling in the progression of cancer-related anemia and revealed a potential therapeutic approach for relieving defects in hematopoiesis.

Male reproductive system ageing is closely associated with deficiency in testosterone production due to loss of functional Leydig cells, which are differentiated from stem Leydig cells (SLCs). However, the relationship between SLC differentiation and ageing remains unknown. In addition, active lipid metabolism during SLC differentiation in the reproductive system requires transportation and processing of substrates among multiple organelles, e.g., mitochondria and endoplasmic reticulum (ER), highlighting the importance of interorganelle contact. Here, we show that SLC differentiation potential declines with disordered intracellular homeostasis during SLC senescence. Mechanistically, loss of the intermediate filament Nestin results in lower differentiation capacity by separating mitochondria-ER contacts (MERCs) during SLC senescence. Furthermore, pharmacological intervention by melatonin restores Nestin-dependent MERCs, reverses SLC differentiation capacity and alleviates male reproductive system ageing. These findings not only explain SLC senescence from a cytoskeleton-dependent MERCs regulation mechanism, but also suggest a promising therapy targeting SLC differentiation for age-related reproductive system diseases.