Monocytes in allo-HSCT with aged donors secrete IL-1/IL-6/TNF to increase the risk of GVHD and damage the aged HSCs.

Aging is considered a critical factor of poor prognosis in allogenic hemopoietic stem cell transplantation (allo-HSCT). To elucidate the underlying mechanisms, we comprehensively reintegrated our clinical data from patients after allo-HSCT and public single-cell transcriptomic profile from post-allo-HSCT and healthy individuals, demonstrating that old donors were more prone to acute GVHD (aGVHD) with pronounced inflammation accumulation and worse overall survival (OS). We also found the presence of inflammation-related CXCL2+ HSC subpopulation during aging with significantly enriched pro-inflammatory pathways. Shifting attention to the HSC microenvironment, we deciphered that IL-1/IL-6 and TRAIL (i.e., TNFSF10) ligand‒receptor pair serves as the crucial bridge between CD14/CD16 monocytes and hematopoietic stem/progenitor cells (HSPCs). The profound upregulation of these signaling pathways during aging finally causes HSC dysfunction and lineage-biased differentiation. Our findings provide the theoretical basis for achieving tailored GVHD management and enhancing allo-HSCT regimens efficacy for aged donors.

Nrf2 for a key member of redox regulation: A novel insight against myocardial ischemia and reperfusion injuries.

Nuclear factor erythroid-2 related factor 2 (Nrf2), a nuclear transcription factor, modulates genes responsible for antioxidant responses against toxic and oxidative stress to maintain redox homeostasis and participates in varieties of cellular processes such as metabolism and inflammation during myocardial ischemia and reperfusion injuries (MIRI). The accumulation of reactive oxygen species (ROS) from damaged mitochondria, xanthine oxidase, NADPH oxidases, and inflammation contributes to depraved myocardial ischemia and reperfusion injuries. Considering that Nrf2 played crucial roles in antagonizing oxidative stress, it is reasonable to delve into the up or down-regulated molecular mechanisms of Nrf2 in the progression of MIRI to provide the possibility of new therapeutic medicine targeting Nrf2 in cardiovascular diseases. This review systematically describes the generation of ROS, the regulatory metabolisms of Nrf2 as well as several natural or synthetic compounds activating Nrf2 during MIRI, which might provide novel insights for the anti-oxidative stress and original ideas targeting Nrf2 for the prevention and treatment in cardiovascular diseases.

High-Performance Planar Field-Emission Photodetector of Monolayer Tungsten Disulfide with Microtips.

Monolayer tungsten disulfide (ML WS2 ) is believed as an ideal photosensitive material due to its small direct bandgap, large exciton/trion binding energy, high carrier mobility, and considerable quantum conversion efficiency. Compared with other photosensitive devices, planar field emission (FE)-type photodetectors with a full-plane structure should simultaneously have rapider switching speed and lower power consumption. In this work, ML WS2 microtips are fabricated by electron beam lithography (EBL) way and used to construct a planar FE-type photodetector. By optimization design, ML WS2 with three microtips can exhibit the maximum current density as high as  52 A cm-2 (@300 V µm-1 ), and the largest photoresponsivity is up to 6.8 × 105 A W-1 under green light irradiation, superior to that of many other ML transition metal dichalcogenide (TMDC) detectors. More interestingly, ML WS2 devices with microtips can effectively solve the contradictory problem between large photoresponsivity and rapid switching speed. The excellent photoresponse performances of ML WS2 with microtips should be attributed to their high carrier mobility, sharp emission edge, ultrahigh quantum yield, and unique planar FE device structure. Our research may shed new light on exploring the fabrication technology and photosensitive mechanism of two dimensional (2D) material-based planar FE photodetectors.

A novel design for magnetic tweezers with wide-range temperature control.

Single-molecule manipulation technologies have proven to be powerful tools for studying the molecular mechanisms and physical principles underlying many essential biological processes. However, achieving wide-range temperature control has been challenging due to thermal drift that undermines the stability of the instrument. This limitation has made it difficult to study biomolecules from thermophiles at their physiologically relevant temperatures and has also hindered the convenient measurement of temperature-sensitive biomolecular interactions and the fundamental thermodynamic properties of biomolecules. In this work, we present a novel design of magnetic tweezers that uses a reflective coverslip and dry objective lens to insulate the heat conductance between the sample and the objective lens, enabling stable temperature changes from ambient up to 70°C during experiments without significant thermal drift of the instrument. The performance of the technology is demonstrated through the quantification of the free energy change of a DNA hairpin over a temperature range of 22°C-72°C, from which the entropy and enthalpy changes are determined.

Glia maturation factor-γ is required for initiation and maintenance of hematopoietic stem and progenitor cells.

BACKGROUND: In vertebrates, hematopoietic stem and progenitor cells (HSPCs) emerge from hemogenic endothelium in the floor of the dorsal aorta and subsequently migrate to secondary niches where they expand and differentiate into committed lineages. Glia maturation factor γ (gmfg) is a key regulator of actin dynamics that was shown to be highly expressed in hematopoietic tissue. Our goal is to investigate the role and mechanism of gmfg in embryonic HSPC development. METHODS: In-depth bioinformatics analysis of our published RNA-seq data identified gmfg as a cogent candidate gene implicated in HSPC development. Loss and gain-of-function strategies were applied to study the biological function of gmfg. Whole-mount in situ hybridization, confocal microscopy, flow cytometry, and western blotting were used to evaluate changes in the number of various hematopoietic cells and expression levels of cell proliferation, cell apoptosis and hematopoietic-related markers. RNA-seq was performed to screen signaling pathways responsible for gmfg deficiency-induced defects in HSPC initiation. The effect of gmfg on YAP sublocalization was assessed in vitro by utilizing HUVEC cell line. RESULTS: We took advantage of zebrafish embryos to illustrate that loss of gmfg impaired HSPC initiation and maintenance. In gmfg-deficient embryos, the number of hemogenic endothelium and HSPCs was significantly reduced, with the accompanying decreased number of erythrocytes, myelocytes and lymphocytes. We found that blood flow modulates gmfg expression and gmfg overexpression could partially rescue the reduction of HSPCs in the absence of blood flow. Assays in zebrafish and HUVEC showed that gmfg deficiency suppressed the activity of YAP, a well-established blood flow mediator, by preventing its shuttling from cytoplasm to nucleus. During HSPC initiation, loss of gmfg resulted in Notch inactivation and the induction of Notch intracellular domain could partially restore the HSPC loss in gmfg-deficient embryos. CONCLUSIONS: We conclude that gmfg mediates blood flow-induced HSPC maintenance via regulation of YAP, and contributes to HSPC initiation through the modulation of Notch signaling. Our findings reveal a brand-new aspect of gmfg function and highlight a novel mechanism for embryonic HSPC development.

Fecal microbiota transplantation from young mice rejuvenates aged hematopoietic stem cells by suppressing inflammation.

Hematopoietic stem cell (HSC) aging is accompanied by hematopoietic reconstitution dysfunction, including loss of regenerative and engraftment ability, myeloid differentiation bias, and elevated risks of hematopoietic malignancies. Gut microbiota, a key regulator of host health and immunity, has recently been reported to affect hematopoiesis. However, there is currently limited empirical evidence explaining the direct impact of gut microbiome on aging hematopoiesis. In this study, we performed fecal microbiota transplantation (FMT) from young mice to aged mice and observed a significant increment in lymphoid differentiation and decrease in myeloid differentiation in aged recipient mice. Furthermore, FMT from young mice rejuvenated aged HSCs with enhanced short-term and long-term hematopoietic repopulation capacity. Mechanistically, single-cell RNA sequencing deciphered that FMT from young mice mitigated inflammatory signals, upregulated the FoxO signaling pathway, and promoted lymphoid differentiation of HSCs during aging. Finally, integrated microbiome and metabolome analyses uncovered that FMT reshaped gut microbiota composition and metabolite landscape, and Lachnospiraceae and tryptophan-associated metabolites promoted the recovery of hematopoiesis and rejuvenated aged HSCs. Together, our study highlights the paramount importance of the gut microbiota in HSC aging and provides insights into therapeutic strategies for aging-related hematologic disorders.

Targeting ferroptosis: a novel insight against myocardial infarction and ischemia-reperfusion injuries.

Ferroptosis, a newly discovered form of regulated cell death dependent on iron and reactive oxygen species, is mainly characterized by mitochondrial shrinkage, increased density of bilayer membranes and the accumulation of lipid peroxidation, causing membrane lipid peroxidation and eventually cell death. Similar with the most forms of regulated cell death, ferroptosis also participated in the pathological metabolism of myocardial infarction and myocardial ischemia/reperfusion injuries, which are still the leading causes of death worldwide. Given the crucial roles ferroptosis played in cardiovascular diseases, such as myocardial infarction and myocardial ischemia/reperfusion injuries, it is considerable to delve into the molecular mechanisms of ferroptosis contributing to the progress of cardiovascular diseases, which might offer the potential role of ferroptosis as a targeted treatment for a wide range of cardiovascular diseases. This review systematically summarizes the process and regulatory metabolisms of ferroptosis, discusses the relationship between ferroptosis and myocardial infarction as well as myocardial ischemia/reperfusion injuries, which might potentially provide novel insights for the pathological metabolism and original ideas for the prevention as well as treatment targeting ferroptosis of cardiovascular diseases such as myocardial infarction and myocardial ischemia/reperfusion injuries.

High Responsivity Vacuum Nano-Photodiode Using Single-Crystal CsPbBr3 Micro-Sheet.

Field electron emission vacuum photodiode is promising for converting free-space electromagnetic radiation into electronic signal within an ultrafast timescale due to the ballistic electron transport in its vacuum channel. However, the low photoelectric conversion efficiency still hinders the popularity of vacuum photodiode. Here, we report an on-chip integrated vacuum nano-photodiode constructed from a Si-tip anode and a single-crystal CsPbBr3 cathode with a nano-separation of ~30 nm. Benefiting from the nanoscale vacuum channel and the high surface work function of the CsPbBr3 (4.55 eV), the vacuum nano-photodiode exhibits a low driving voltage of 15 V with an ultra-low dark current (50 pA). The vacuum nano-photodiode demonstrates a high photo responsivity (1.75 AW-1@15 V) under the illumination of a 532-nm laser light. The estimated external quantum efficiency is up to 400%. The electrostatic field simulation indicates that the CsPbBr3 cathode can be totally depleted at an optimal thickness. The large built-in electric field in the depletion region facilitates the dissociation of photoexcited electron-hole pairs, leading to an enhanced photoelectric conversion efficiency. Moreover, the voltage drop in the vacuum channel increases due to the photoconductive effect, which is beneficial to the narrowing of the vacuum barrier for more efficient electron tunneling. This device shows great promise for the development of highly sensitive perovskite-based vacuum opto-electronics.

Protocol for correlation analysis of the murine gut microbiome and meta-metabolome using 16S rDNA sequencing and UPLC-MS.

The gut microbiota and metabolites play pivotal roles in the pathobiology of various diseases. Here, we describe a protocol to profile the gut microbiome and meta-metabolome of a mouse disease model for acute graft-versus-host disease. We describe steps for fecal sample collection and processing for 16S sequencing and UPLC-MS. Finally, we detail the steps for data analysis and exhibit multi-omic associations to correlate with pathology. For complete details on the use and execution of this protocol, please refer to Li et al. (2020).

Development and Validation of an Individualized Metabolism-Related Prognostic Model for Adult Acute Myeloid Leukemia Patients.

Objectives: Acute myeloid leukemia (AML) is a highly heterogeneous hematologic malignancy with widely variable prognosis. For this reason, a more tailored-stratified approach for prognosis is urgently needed to improve the treatment success rates of AML patients. Methods: In the investigation of metabolic pattern in AML patients, we developed a metabolism-related prognostic model, which was consisted of metabolism-related gene pairs (MRGPs) identified by pairwise comparison. Furthermore, we analyzed the predictive ability and clinical significance of the prognostic model. Results: Given the significant differences in metabolic pathways between AML patients and healthy donors, we proposed a metabolism-related prognostic signature index (MRPSI) consisting of three MRGPs, which were remarkedly related with the overall survival of AML patients in the training set. The association of MRPSI with prognosis was also validated in two other independent cohorts, suggesting that high MRPSI score can identify patients with poor prognosis. The MRPSI and age were confirmed to be independent prognostic factors via multivariate Cox regression analysis. Furthermore, we combined MRPSI with age and constructed a composite metabolism-clinical prognostic model index (MCPMI), which demonstrated better prognostic accuracy in all cohorts. Stratification analysis and multivariate Cox regression analysis revealed that the MCPMI was an independent prognostic factor. By estimating the sensitivity of anti-cancer drugs in different AML patients, we selected five drugs that were more sensitive to patients in MCPMI-high group than those in MCPMI-low group. Conclusion: Our study provided an individualized metabolism-related prognostic model that identified high-risk patients and revealed new potential therapeutic drugs for AML patients with poor prognosis.

Soluble RAGE attenuates myocardial I/R injuries via FoxO3-Bnip3 pathway.

Soluble receptor for advanced glycation end-products (sRAGE) was reported to inhibit cardiac apoptosis through the mitochondrial pathway during myocardial ischemia/reperfusion (I/R) injury. Meanwhile, the proapoptotic protein Bcl2 and adenovirus E1B 19-kDa-interacting protein 3 (Bnip3) was reported to mediate mitochondrial depolarization and be activated by the Forkhead box protein O3 (FoxO3a). Therefore, it is supposed that FoxO3a-Bnip3 pathway might be involved in the inhibiting effects of sRAGE on mitochondrial apoptosis during I/R. I/R surgery or glucose deprivation/reoxygenation was adopted to explore mitochondrial depolarization, apoptosis and related signaling pathways in mice hearts and cultured cardiomyocytes. The results showed that overexpression of sRAGE in cardiomyocytes dramatically improved cardiac function and reduced infarct areas in I/R treated mice. sRAGE inhibited mitochondrial depolarization and cardiac apoptosis during I/R, which correlated with reduced expression of Bnip3, Sirt2, phosphorylation of Akt and FoxO3a which translocated into nucleus in cultured cardiomyocytes. Either Sirt2 or FoxO3a silencing enhanced the inhibiting effects of sRAGE on mitochondrial depolarization induced by I/R in cultured cardiomyocytes. Meanwhile, overexpression or silencing of FoxO3a affected the inhibiting effects of sRAGE on Bnip3 and cleaved caspase-3 in cultured cardiomyocytes. Therefore, it is suggested that sRAGE inhibited I/R injuries via reducing mitochondrial apoptosis through the FoxO3a-Bnip3 pathway.

Correction: Transcriptional Effects of E3 Ligase Atrogin-1/MAFbx on Apoptosis, Hypertrophy and Inflammation in Neonatal Rat Cardiomyocytes.

[This corrects the article DOI: 10.1371/journal.pone.0053831.].

Integrinß3 mediates the protective effects of soluble receptor for advanced glycation end-products during myocardial ischemia/reperfusion through AKT/STAT3 signaling pathway.

Soluble receptor for advanced glycation end-product (sRAGE) was reported to protect myocardial ischemia/reperfusion (I/R) injuries via directly interacting with cardiomyocytes besides competing with RAGE for AGEs. However, the specific molecule for the interaction between sRAGE and cardiomyocytes are not clearly defined. Integrins which were reported to interact with RAGE on leukocytes were also expressed on myocardial cells, therefore it was supposed that sRAGE might interact with integrins on cardiomyocytes to protect hearts from ischemia/reperfusion injuries. The results showed that sRAGE increased the expression of integrinß3 but not integrinß1, ß2, ß4 or ß5 in cardiomyocytes during I/R injuries. Meanwhile, the suppressive effects of sRAGE on cardiac function, cardiac infraction size and apoptosis in mice were cancelled by inhibition of integrinß3 with cilengitide (CLG, 75 mg/kg). The results from cultured cardiomyocytes also proved that sRAGE attenuated myocardial apoptosis and autophagy through interacting with integrinß3 to activate Akt and STAT3 pathway during oxygen and glucose deprivation/reperfusion (OGD/R) treatment. Furthermore, the phosphorylation of STAT3 was significantly downregulated by the inhibition of Akt (LY294002, 10 µM) in OGD/R and sRAGE treated cardiomyocytes, which suggested that STAT3 pathway was induced by Akt in I/R and sRAGE treated cardiomyocytes. The present study contributes to the understanding of myocardial I/R pathogenesis and provided a novel integrinß3-dependent therapy strategy for sRAGE ameliorating I/R injuries.

Cyclosporine A regulates PMN-MDSCs viability and function through MPTP in acute GVHD: Old medication, new target.

Myeloid-derived suppressor cells (MDSCs), a population of myeloid lineage cells with immunosuppressive capacity, can mitigate acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We previously found that the immunosuppressive function of polymorphonuclear population (PMN-MDSCs) was impaired in aGVHD milieu. The aim of this study was to explore the intrinsic mechanism regulating the fate and function of donor-derived PMN-MDSCs during allo-HSCT. We firstly found that mitochondrial permeability transition pore (MPTP) opened in the PMN-MDSCs in response to the intense inflammatory environment of aGVHD, which induced mitochondrial damage, oxidative stress, and apoptosis of PMN-MDSCs. Inhibiting MPTP opening by a traditional immunosuppressant, cyclosporine A (CsA), could restore the immunosuppressive function and viability of PMN-MDSCs in vitro and in vivo, which reveals a new mechanism of CsA application.

Efficient expansion of rare human circulating hematopoietic stem/progenitor cells in steady-state blood using a polypeptide-forming 3D culture.

Although widely applied in treating hematopoietic malignancies, transplantation of hematopoietic stem/progenitor cells (HSPCs) is impeded by HSPC shortage. Whether circulating HSPCs (cHSPCs) in steady-state blood could be used as an alternative source remains largely elusive. Here we develop a three-dimensional culture system (3DCS) including arginine, glycine, aspartate, and a series of factors. Fourteen-day culture of peripheral blood mononuclear cells (PBMNCs) in 3DCS led to 125- and 70-fold increase of the frequency and number of CD34+ cells. Further, 3DCS-expanded cHSPCs exhibited the similar reconstitution rate compared to CD34+ HSPCs in bone marrow. Mechanistically, 3DCS fabricated an immunomodulatory niche, secreting cytokines as TNF to support cHSPC survival and proliferation. Finally, 3DCS could also promote the expansion of cHSPCs in patients who failed in HSPC mobilization. Our 3DCS successfully expands rare cHSPCs, providing an alternative source for the HSPC therapy, particularly for the patients/donors who have failed in HSPC mobilization.

Protective Effects of the Soluble Receptor for Advanced Glycation End-Products on Pyroptosis during Myocardial Ischemia-Reperfusion.

Ischemia-reperfusion injury (IRI) is an inevitable process when reperfusion therapy undergoes in acute myocardial infarction patients, which will lead to cardiac cell death. Many factors have been found to protect the myocardium, one of which was the soluble receptor for advanced glycation end-products (sRAGE) that protected the myocardium from apoptosis and autophagy. However, pyroptosis is also an important form of cell death that occurs during ischemia-reperfusion (I/R), whose critical molecule, NLR family pyrin domain containing 3 (NLRP3), was ever reported to be inhibited by sRAGE; therefore, it is hypothesized that sRAGE may decrease the cardiac pyroptosis induced by I/R. The results showed that sRAGE protected cardiomyocytes from I/R-induced pyroptosis by decreasing the expression level of NLRP3, gasdermin D (GSDMD), interleukin-1ß (IL-1ß), and interleukin-18 (IL-18). Meanwhile, the results from primary cultured cardiomyocytes showed that the NF-κB pathway mediated the effects of sRAGE on pyroptosis. Therefore, it is concluded that sRAGE protects the heart from pyroptosis through inhibiting the NF-κB pathway during myocardial ischemia-reperfusion.

Integrated Single-Cell Bioinformatics Analysis Reveals Intrinsic and Extrinsic Biological Characteristics of Hematopoietic Stem Cell Aging.

Hematopoietic stem cell (HSC) aging, which is accompanied by loss of self-renewal capacity, myeloid-biased differentiation and increased risks of hematopoietic malignancies, is an important focus in stem cell research. However, the mechanisms underlying HSC aging have not been fully elucidated. In the present study, we integrated 3 independent single-cell transcriptome datasets of HSCs together and identified Stat3 and Ifngr1 as two markers of apoptosis-biased and inflammatory aged HSCs. Besides, common differentially expressed genes (DEGs) between young and aged HSCs were identified and further validated by quantitative RT-PCR. Functional enrichment analysis revealed that these DEGs were predominantly involved in the cell cycle and the tumor necrosis factor (TNF) signaling pathway. We further found that the Skp2-induced signaling pathway (Skp2→Cip1→CycA/CDK2→DP-1) contributed to a rapid transition through G1 phase in aged HSCs. In addition, analysis of the extrinsic alterations on HSC aging revealed the increased expression levels of inflammatory genes in bone marrow microenvironment. Colony formation unit assays showed that inflammatory cytokines promoted cellular senescence and that blockade of inflammatory pathway markedly rejuvenated aged HSC functions and increased B cell output. Collectively, our study elucidated the biological characteristics of HSC aging, and the genes and pathways we identified could be potential biomarkers and targets for the identification and rejuvenation of aged HSCs.

Signaling pathways in the regulation of cytokine release syndrome in human diseases and intervention therapy.

Cytokine release syndrome (CRS) embodies a mixture of clinical manifestations, including elevated circulating cytokine levels, acute systemic inflammatory symptoms and secondary organ dysfunction, which was first described in the context of acute graft-versus-host disease after allogeneic hematopoietic stem-cell transplantation and was later observed in pandemics of influenza, SARS-CoV and COVID-19, immunotherapy of tumor, after chimeric antigen receptor T (CAR-T) therapy, and in monogenic disorders and autoimmune diseases. Particularly, severe CRS is a very significant and life-threatening complication, which is clinically characterized by persistent high fever, hyperinflammation, and severe organ dysfunction. However, CRS is a double-edged sword, which may be both helpful in controlling tumors/viruses/infections and harmful to the host. Although a high incidence and high levels of cytokines are features of CRS, the detailed kinetics and specific mechanisms of CRS in human diseases and intervention therapy remain unclear. In the present review, we have summarized the most recent advances related to the clinical features and management of CRS as well as cutting-edge technologies to elucidate the mechanisms of CRS. Considering that CRS is the major adverse event in human diseases and intervention therapy, our review delineates the characteristics, kinetics, signaling pathways, and potential mechanisms of CRS, which shows its clinical relevance for achieving both favorable efficacy and low toxicity.

Specific Blood Cells Derived from Pluripotent Stem Cells: An Emerging Field with Great Potential in Clinical Cell Therapy.

Widely known for self-renewal and multilineage differentiation, stem cells can be differentiated into all specialized tissues and cells in the body. In the past few years, a number of researchers have focused on deriving hematopoietic stem cells (HSCs) from pluripotent stem cells (PSCs) as alternative sources for clinic. Existing findings demonstrated that it is feasible to obtain HSCs and certain mature blood lineages from PSCs, except for several issues to be addressed. This short review outlines the technologies used for hematopoietic differentiation in recent years. In addition, the therapeutic value of PSCs as a potential source of various blood cells is also discussed as well as its challenges and directions in future clinical applications.