Lipopolysaccharide induces aging phenotype of hematopoietic stem cells in bone marrow and spleen of young mice / 中国病理生理杂志

AIM:This study aim to investigate the effects of lipopolysaccharide(LPS)-induced inflammation on the aging phenotype of hematopoietic stem/progenitor cells(HSPCs)in the bone marrow(BM)and spleen of mice.METHODS:(1)Young(2-month old)wild-type(WT)mice were treated with LPS to establish an actue inflammation model.The percentage of HSPCs in the BM and spleen of mice after LPS stimulation,as well as the ratio of mature cells in peripheral blood(PB)and spleen,were analyzed using flow cytometry.The proliferation of HSPCs in the BM and spleen was evaluated by examining the expression of the proliferation marker Ki67.In addition,changes in CD45 expression on HSPCs in the spleen of mice following LPS exposure were investigated by flow cytometry.(2)The percentage of HSPCs in BM and mature cells in PB and spleen of both young(2-month old)and old(24-month old)WT mice were analyzed by flow cytometry.(3)The transcriptome changes of hematopoietic stem cells(HSCs)after LPS stimulation was performed by an in silico analysis.RESULTS:(1)Mice exposed to LPS exhibited a significant increase in the percentage of HSPCs in BM and a marked elevation in the percentages of myeloid cells in PB and spleen compared to the mice in control group(P<0.05).(2)LPS exposure resulted in increased spleen weight and cell counts(P<0.05),along with a higher per-centage of HSPCs in the spleen compared to controls(P<0.05).(3)LPS stimulation promoted the proliferation of HSPCs in the BM and spleen(P<0.05).(4)The expression of CD45 was reduced on HSPCs from spleen of mice after LPS stimu-lation(P<0.01).(5)In comparison to young mice,aged mice showed an increase in spleen weight and a higher percent-age of HSPCs in the spleen(P<0.05).(6)Aged mice,in comparison to young mice,demonstrated a significantly higher percentage of HSPCs in the BM and myeloid skewing in the PB and spleen(P<0.01).(7)The silico analysis revealed up-regualtion of reactive oxygen species(ROS)and apoptosis signaling in HSPCs following LPS stimulation.CONCLU-SION:Young HSPCs stimulated by LPS exhibited an increase in cell number,a bias towards myeloid differentiation,en-hanced extramedullary hematopoiesis,and elevated levels of ROS and apoptosis,all of which collectively manifested the aging phenotype of HSPCs.

Knockdown of SMARCA4 leads to ferroptosis of HT1080 cells through inhibition of cholesterol synthesis / 中国病理生理杂志

AIM:To investigate the role and molecular mechanisms of SMARCA4(SWI/SNF-related,matrix-associated,actin-dependent regulator of chromatin,subfamily A,member 4)in ferroptosis.METHODS:(1)Human fi-brosarcoma HT1080 cells were treated with dimethyl sulfoxide(DMSO)and different concentrations(31.25,62.5 and 125 nmol/L)of Ras-selective lethal small molecule 3(RSL3;ferroptosis inducer).Each treatment had 3 replicate wells of cells.The protein levels of SMARCA4 were detected by Western blot.(2)Two small interfering RNAs(siSMARCA4-1 and siSMARCA4-2)were constructed according to the SMARCA4 gene sequence.After SMARCA4 knockdown,each treat-ment had 3 replicate wells of cells,and the protein levels of SMARCA4 were determined by Western blot.Effects of DMSO,necrostatin 2 racemate(Nec-1s;necroptosis inhibitor),Z-VAD(OMe)-FMK(Z-VAD,pan-caspase inhibitor/apoptosis inhibitor)and ferrostatin-1(Fer-1,ferroptosis inhibitor)on cell viability were assessed using high-content analy-sis.The levels of ferroptosis indicators,including prostaglandin-endoperoxide synthase 2(PTGS2)transcription,lipid peroxidation,reactive oxygen species(ROS),labile iron pool(LIP)and glutathione,were determined by RT-qPCR and flow cytometry.The mRNA expression levels of pivotal iron metabolism genes,ferroptosis-related ROS regulatory genes,and cholesterol synthesis-related genes were measured using RT-qPCR.Impact of cholesterol on the cell viability were as-sessed using high-content analysis.(3)Common differential gene analysis and gene ontology(GO)enrichment analysis were performed on published online data.RESULTS:(1)Treatment with RSL3 significantly reduced the protein level of SMARCA4(P＜0.05).(2)Knockdown of SMARCA4 resulted in ferroptosis.(3)Knockdown of SMARCA4 did not induce ferroptosis by modulating the LIP and the transcription levels of ROS-related genes.(4)Knockdown of SMARCA4 affected the pathways associated with the cell membrane,lipid raft,and cholesterol synthesis.(5)Addition of cholesterol to cell culture medium rescued the ferroptosis induced by SMARCA4 knockdown(P＜0.01).CONCLUSION:Treatment with RSL3 reduces the protein level of SMARCA4 in human fibrosarcoma HT1080 cells,and inhibition of cholesterol synthesis by SMARCA4 knockdown leads to the ferroptosis of HT1080 cells.

Advances in the research of cytokine storm mechanism induced by Corona Virus Disease 2019 and the corresponding immunotherapies / 中华烧伤杂志

Corona Virus Disease 2019 (COVID-19) has seriously affected the treatment of patients and social stability. In the later stage of disease, some COVID-19 patients may develop into acute respiratory distress syndrome or even multiple organ failure. However, one of the most important mechanism underlying the deterioration of disease is cytokine storm. At present, some therapies such as interleukin-6 antibody blocker, stem cell therapy, and transfusion of convalescent plasma have been applied to counteract the cytokine storm and have made some progress. This article reviews the influences of cytokine storm syndrome on the COVID-19 and the corresponding immunotherapies to resist cytokine storm.

CXCL-13 Regulates Resistance to 5-Fluorouracil in Colorectal Cancer / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#5-Fluorouracil (5-Fu) is used as a conventional chemotherapy drug in chemotherapy forpatients with advanced colorectal cancer, but many patients still suffer from treatment failuredue to 5-Fu resistance. Emerging observations revealed the important role of chemokine(C-X-C motif) ligand 13 (CXCL-13) in tumor microenvironment and its relationship with prognosisin patients with colorectal cancer. This study is designed to reveal the important roleof CXCL-13 in causing colorectal cancer resistance to 5-Fu. @*Materials and Methods@#CXCL-13 levels of patient's serum or cell culture supernatants were measured separatelyby enzyme-linked immunosorbent assay. In cell assays, cell viability is detected by Cell CountingKit-8. Therefore, the recombinant human CXCL-13 was used to simulate its high expressionin cells while its antibody and siRNA were used to reduce CXCL-13 expression in cells. @*Results@#In this study, we demonstrated that CXCL-13 is associated with 5-Fu resistance by culturemedium exchange experiments and cytokine arrays of colorectal cancer resistant and nonresistantcells. Clinical studies showed that CXCL-13 is highly expressed in the serum of5-Fu–resistant patients. High levels of serum CXCL-13 also predict a worse clinical outcome.The addition of recombinant CXCL-13 cytokine resulted in 5-Fu resistance, while its antibodyovercame 5-Fu resistance, and knockdown of CXCL-13 expression by siRNA also reduced5-Fu resistance, which can be saved by added recombination CXCL-13. @*Conclusion@#These results not only identify a CXCL-13 mediated 5-Fu resistance mechanism but alsoprovide a novel target for 5-Fu–resistant colorectal cancer in prevention and treatmentstrategies.

Chemical screen identifies a geroprotective role of quercetin in premature aging

Aging increases the risk of various diseases. The main goal of aging research is to find therapies that attenuate aging and alleviate aging-related diseases. In this study, we screened a natural product library for geroprotective compounds using Werner syndrome (WS) human mesenchymal stem cells (hMSCs), a premature aging model that we recently established. Ten candidate compounds were identified and quercetin was investigated in detail due to its leading effects. Mechanistic studies revealed that quercetin alleviated senescence via the enhancement of cell proliferation and restoration of heterochromatin architecture in WS hMSCs. RNA-sequencing analysis revealed the transcriptional commonalities and differences in the geroprotective effects by quercetin and Vitamin C. Besides WS hMSCs, quercetin also attenuated cellular senescence in Hutchinson-Gilford progeria syndrome (HGPS) and physiological-aging hMSCs. Taken together, our study identifies quercetin as a geroprotective agent against accelerated and natural aging in hMSCs, providing a potential therapeutic intervention for treating age-associated disorders.

CRISPR/Cas9-mediated gene knockout reveals a guardian role of NF-κB/RelA in maintaining the homeostasis of human vascular cells

Vascular cell functionality is critical to blood vessel homeostasis. Constitutive NF-κB activation in vascular cells results in chronic vascular inflammation, leading to various cardiovascular diseases. However, how NF-κB regulates human blood vessel homeostasis remains largely elusive. Here, using CRISPR/Cas9-mediated gene editing, we generated RelA knockout human embryonic stem cells (hESCs) and differentiated them into various vascular cell derivatives to study how NF-κB modulates human vascular cells under basal and inflammatory conditions. Multi-dimensional phenotypic assessments and transcriptomic analyses revealed that RelA deficiency affected vascular cells via modulating inflammation, survival, vasculogenesis, cell differentiation and extracellular matrix organization in a cell type-specific manner under basal condition, and that RelA protected vascular cells against apoptosis and modulated vascular inflammatory response upon tumor necrosis factor α (TNFα) stimulation. Lastly, further evaluation of gene expression patterns in IκBα knockout vascular cells demonstrated that IκBα acted largely independent of RelA signaling. Taken together, our data reveal a protective role of NF-κB/RelA in modulating human blood vessel homeostasis and map the human vascular transcriptomic landscapes for the discovery of novel therapeutic targets.

Gadd45a deletion aggravates hematopoietic stem cell dysfunction in ATM-deficient mice

Ataxia telangiectasia mutated (ATM) kinase plays an essential role in the maintenance of genomic stability. ATM-deficient (ATM(-/-)) mice exhibit hematopoietic stem cell (HSC) dysfunction and a high incidence of lymphoma. Gadd45a controls cell cycle arrest, apoptosis and DNA repair, and is involved in the ATM-p53 mediated DNA damage response. However, the role of Gadd45a in regulating the functionality of ATM(-/-) HSCs is unknown. Here we report that Gadd45a deletion did not rescue the defects of T-cells and B-cells development in ATM(-/-) mice. Instead, ATM and Gadd45a double knockout (ATM(-/-) Gadd45a(-/-)) HSCs exhibited an aggravated defect in long-term self-renewal capacity compared to ATM(-/-) HSCs in HSC transplantation experiments. Further experiments revealed that the aggravated defect of ATM(-/-) Gadd45a(-/-) HSCs was due to a reduction of cell proliferation, associated with an accumulation of DNA damage and subsequent activation of DNA damage response including an up-regulation of p53-p21 signaling pathway. Additionally, ATM(-/-) Gadd45a(-/-) mice showed an increased incidence of hematopoietic malignancies, as well as an increased rate of metastasis than ATM(-/-) mice. In conclusion, Gadd45a deletion aggravated the DNA damage accumulation, which subsequently resulted in a further impaired self-renewal capacity and an increased malignant transformation in ATM(-/-) HSCs.