摘要: Cortical bone loss is intricately associated with ageing and coincides with iron accumulation. The precise role of ferroptosis, characterized by iron overload and lipid peroxidation, in senescent osteocytes remains elusive. We found that ferroptosis was a crucial mode of osteocyte death in cortical bone during ageing. Using a single-cell transcriptome analysis, we identified activating transcription factor 3 (ATF3) as a critical driver of osteocyte ferroptosis. Elevated ATF3 expression in senescent osteocytes promotes iron uptake by upregulating transferrin receptor 1 while simultaneously inhibiting solute carrier family 7-member 11-mediated cystine import. This process leads to an iron overload and lipid peroxidation, culminating in ferroptosis. Importantly, ATF3 inhibition in aged mice effectively alleviated ferroptosis in the cortical bone and mitigated cortical bone mass loss. Taken together, our findings establish a pivotal role of ferroptosis in cortical bone loss in older adults, providing promising prevention and treatment strategies for osteoporosis and fractures.

摘要: Ex vivo red blood cell (RBC) production generates unsatisfactory erythroid cells. A deep exploration into terminally differentiated cells is required to understand the impairments for RBC generation and the underlying mechanisms. Here, we mapped an atlas of terminally differentiated cells from umbilical cord blood mononuclear cells (UCBMN) and pluripotent stem cells (PSC) and observed their dynamic regulation of erythropoiesis at single-cell resolution. Interestingly, we detected a few progenitor cells and non-erythroid cells from both origins. In PSC-derived erythropoiesis (PSCE), the expression of haemoglobin switch regulators (BCL11A and ZBTB7A) were significantly absent, which could be the restraint for its adult globin expression. We also found that PSCE were less active in stress erythropoiesis than in UCBMN-derived erythropoiesis (UCBE), and explored an agonist of stress erythropoiesis gene, TRIB3, could enhance the expression of adult globin in PSCE. Compared with UCBE, there was a lower expression of epigenetic-related proteins (e.g., CASPASE 3 and UBE2O) and transcription factors (e.g., FOXO3 and TAL1) in PSCE, which might restrict PSCE's enucleation. Moreover, we characterized a subpopulation with high proliferation capacity marked by CD99high in colony-forming unit-erythroid cells. Inhibition of CD99 reduced the proliferation of PSC-derived cells and facilitated erythroid maturation. Furthermore, CD99-CD99 mediated the interaction between macrophages and erythroid cells, illustrating a mechanism by which macrophages participate in erythropoiesis. This study provided a reference for improving ex vivo RBC generation. scRNA-seq and cell typing of late-stage umbilical cord blood mononuclear cells- and pluripotent stem cell (PSC)-derived cells were conducted. Stress erythropoiesis was more active in UCBMN-derived erythropoiesis (UCB-E) than in PSC-derived erythropoiesis (PSC-E). Regulators that impair adult globin expression and enucleation between UCB-E and PSC-E were compared at single cell level. CD99high progenitor cells were a proliferating colony forming unit erythroid subpopulation. image

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摘要: Identification of the epidermal growth factor receptor (EGFR) in biological specimens is essential for cancer diagnostics, drug development and therapeutic monitoring. However, real-time techniques for accurate EGFR expression monitoring are currently limited. In this study, we report the development of a novel nano detector (Cy3-AptEGFR@BPNSs) with the capabilities of quenching and recovery to enable visual EGFR expression analysis. Cy3-AptEGFR is a Cy3-labelled single-stranded RNA (ssRNA) that exhibits specific binding to EGFR. Black phosphorus nanosheets (BPNSs) possess the ability to adsorb Cy3-AptEGFR via van der Waals forces, quenching its fluorescence when combined. The detection of EGFR receptors on cancer cell surfaces prompts the release of Cy3-AptEGFR from BPNSs, a consequence of the robust binding interaction between the receptor and aptamer, thereby leading to fluorescence reinstatement. The recovered fluorescence intensity of this detector is found to be directly correlated with EGFR expression levels in cancer cells, indicating its potential for guiding tumour diagnosis and treatment. The specificity of Cy3-AptEGFR@BPNSs further enhances its utility in detecting EGFR. More importantly, our research demonstrates that the reduction in EGFR expression levels within cancer cells corresponds to a proportional decline in fluorescence intensity, thereby facilitating precise tracking of EGFR dynamics.

摘要: Microglia, considered as the main immune responder, play an important role in regulating neuroinflammation in central nervous system (CNS) disorders. Our previous work found that TREM2 is highly expressed in microglia and is related to their functional state. However, the specific role of TREM2 in spinal cord injury has not yet been explored. To further investigate the potential mechanism of TREM2, we performed single-cell sequencing on wild-type (Wt) and Trem2-/- mice before and after spinal cord injury. Compared to Wt mice, the lysosome, autophagy and membrane-related pathways are more strongly activated in Trem2-/- mice, suggesting that TREM2 may exert its effects by influencing lysosomal membranes and autophagy. Mechanistically, we demonstrated that the knockout of Trem2 can reduce the nuclear translocation of TFEB by decreasing the phosphorylation of Syk. Furthermore, we validated that in vitro and in vivo silencing Trem2 can promote autophagy by repairing lysosomal membrane permeabilization. Through immunofluorescence, 3D gait analysis, motor evoked potential experiments, H&E staining and Masson staining, we demonstrated that the increased level of autophagy can rescue more microglia in vivo and promote both functional and histological recovery of spinal cord injury. Collectively, these results not only suggest that microglial lysosomal autophagy is regulated in a TREM2-dependent LMP manner, but also, more importantly, they provide a promising clinical translation strategy based on gene therapy for lysosome-related central nervous system disorders.

摘要: The treatment of postmenopausal osteoporosis (OP) presents a multifaceted challenge. Nonetheless, emerging research indicates a significant association between the N6-methyladenosine (m6A) methylase METTL3 and osteogenesis in OP. To investigate Mettl3's impact on osteogenic potential and the underlying molecular mechanisms, an OP rat model was established via ovariectomy (OVX). Osteoporotic adipose-derived stem cells (OP-ASCs) were then isolated. Results indicated a significant downregulation of Mettl3 expression in OP-ASCs. Subsequently, OP-ASCs were transfected with overexpressed Mettl3 lentivirus and treated for Dickkopf-related protein-1 (DKK1). Overexpression of the Mettl3 gene led to increased levels of osteogenic factors. DKK1 attenuated osteoblastic differentiation capacity in the Mettl3 overexpression group by inhibiting the Wnt signalling pathway. Consistent results were observed in vivo experiments. In conclusion, overexpression of Mettl3 promotes osteogenesis in OP-ASCs by activating the Wnt/beta-catenin pathway.

摘要: The de-ubiquitinase USP33 has been shown to possess either tumour-promoting or inhibitory effect on human cancer cells. However, all these findings are mainly based on in vitro cell culture models, and the in vivo evidence, which is more plausible to digest the functional role of USP33 in carcinogenic process, is still lacking. Here, we demonstrate that USP33 modulates DNA damage responses including cell cycle arrest and apoptosis induction through associating with p53. It directly interacts with p53 to mediate its de-ubiquitination and further stabilisation under DNA damage condition. Depletion of USP33 induces an enhanced level of p53 ubiquitination, which de-stabilises p53 protein leading to impaired DNA damage responses. Furthermore, USP33 silencing shows either promoted or inhibited effect on cell proliferation in human cancer cells with p53 WT and mutant background, respectively. Consistently, mice with hepatocyte-specific USP33 knockout are more sensitive to nitrosodiethylamine (DEN)-induced hepatocarcinogenesis compared to wild type mice. Thus, our in vitro and in vivo evidences illustrate that USP33 possesses anti-tumour activity via regulating p53 stability and activity.

摘要: Growing evidence indicates that the deterioration of egg quality caused by postovulatory ageing significantly hampers embryonic development. However, the molecular mechanisms by which postovulatory ageing leads to a decline in oocyte quality have not been fully characterized. In this study, we observed an accelerated decay of maternal mRNAs through RNA-seq analyses in postovulatory-aged (PostOA) oocytes. We noted that these downregulated mRNAs should be degraded during the 2-cell stage. Proteomic analyses revealed that the degradation of maternal mRNAs is associated with the accumulation of DCP1A. The injection of exogenous Dcp1a mRNA or siRNA into MII stage oocytes proved that DCP1A could accelerate the degradation of maternal mRNAs. Additionally, we also found that SPDL1 is crucial for maintaining spindle/chromosome structure and chromosome euploidy in PostOA oocytes. Spdl1-mRNA injection remarkably recovered the meiotic defects in PostOA oocytes. Collectively, our findings provide valuable insights into the molecular mechanisms underlying postovulatory ageing.

摘要: Inducing tertiary lymphoid structure (TLS) formation can fuel antitumor immunity. It is necessary to create mouse models containing TLS to explore strategies of TLS formation. Oncolytic herpes simplex virus-1 (oHSV) exhibited intense effects in preclinical and clinical trials. However, the role of oHSV in TLS formation remains to be elucidated. Here, we observed the presence of TLS in 4MOSC1 and MC38 subcutaneous tumour models. Interestingly, oHSV evoked TLS formation, and increased infiltration of B cells and stem-like TCF1(+)CD8(+) T cells proliferation. Mechanistically, oHSV increased the expression of TLS-related chemokines, along with upregulated CXCL10/CXCR3 to facilitate TLS formation. Notably, CXCL10 and CXCR3 were favourable prognostic factors for cancer patients, and closely related with immune cells infiltration. Inhibiting CXCL10/CXCR3 reduced TCF1(+)CD8(+) T cells and granzyme B expression, and impaired oHSV-mediated TLS formation. Furthermore, oHSV-mediated TLS formation revealed superior response and survival rate when combined with alpha PD-1 treatment. Collectively, these findings indicate that oHSV recruits stem-like TCF1(+)CD8(+) T cells through CXCL10/CXCR3 pathway to propagate TLS formation, and warrants future antitumor immunity development.

摘要: Given the growing interest in the metabolic heterogeneity of hepatocellular carcinoma (HCC) and portal vein tumour thrombus (PVTT). This study comprehensively analysed the metabolic heterogeneity of HCC, PVTT, and normal liver samples using multi-omics combinations. A single-cell RNA sequencing dataset encompassing six major cell types was obtained for integrated analysis. The optimal subtypes were identified using cluster stratification and validated using spatial transcriptomics and fluorescent multiplex immunohistochemistry. Then, a combined index based meta-cluster was calculated to verify its prognostic significance using multi-omics data from public cohorts. Our study first depicted the metabolic heterogeneity landscape of non-malignant cells in HCC and PVTT at multiomics levels. The optimal subtypes interpret the metabolic characteristics of PVTT formation and development. The combined index provided effective predictions of prognosis and immunotherapy responses. Patients with a higher combined index had a relatively poor prognosis (p <0.001). We also found metabolism of polyamines was a key metabolic pathway involved in conversion of metabolic heterogeneity in HCC and PVTT, and identified ODC1 was significantly higher expressed in PVTT compared to normal tissue (p =0.03). Our findings revealed both consistency and heterogeneity in the metabolism of non-malignant cells in HCC and PVTT. The risk stratification based on cancer-associated fibroblasts and myeloid cells conduce to predict prognosis and guide treatment. This offers new directions for understanding disease development and immunotherapy responses.