The Regulatory Role of IFN-γ on the Proliferation and Differentiation of Hematopoietic Stem and Progenitor Cells

Impact of donor NKG2D and MICA gene polymorphism on clinical outcomes of adult and paediatric allogeneic cord blood transplantation for malignant diseases

OBJECTIVES

NKG2D is an activating receptor expressed by natural killer (NK) and CD8+ T cells and activation intensity varies by NKG2D expression level or nature of its ligand. An NKG2D gene polymorphism determines high (HNK1) or low (LNK1) expression. MICA is the most polymorphic NKG2D ligand and stronger effector cell activation associates with methionine rather than valine at residue 129. We investigated correlation between cord blood (CB) NKG2D and MICA genotypes and haematopoietic stem cell (HSC) transplant outcome.

METHODS

We retrospectively studied 267 CB HSC recipients (178 adult and 87 paediatric) who underwent transplant for malignant disease between 2007 and 2018, analysing CB graft DNA for NKG2D and MICA polymorphisms using Sanger sequencing. Multivariate analysis was used to correlate these results with transplant outcomes.

RESULTS

In adult patients, LNK1 homozygous CB significantly improved 60-day neutrophil engraftment (hazard ratio (HR) 0.6; 95% confidence interval (CI) 0.4-0.9; p = .003). In paediatrics, HNK1 homozygous CB improved 60-day engraftment (HR 0.4; 95% CI 0.2-0.7; p = .003), as did MICA-129 methionine+ CB grafts (HR 1.7 95% CI 1.1-2.6; p = .02).

CONCLUSION

CB NKG2D and MICA genotypes potentially improve CB HSC engraftment. However, results contrast between adult and paediatric recipients and may reflect transplant procedure disparities between cohorts.

A Perfect Storm: The Convergence of Aging, Human Immunodeficiency Virus Infection, and Inflammasome Dysregulation

The emergence of combination antiretroviral therapy (cART) has greatly transformed the life expectancy of people living with HIV (PWH). Today, over 76% of the individuals with HIV have access to this life-saving therapy. However, this progress has come with a new challenge: an increase in age-related non-AIDS conditions among patients with HIV. These conditions manifest earlier in PWH than in uninfected individuals, accelerating the aging process. Like PWH, the uninfected aging population experiences immunosenescence marked by an increased proinflammatory environment. This phenomenon is linked to chronic inflammation, driven in part by cellular structures called inflammasomes. Inflammatory signaling pathways activated by HIV-1 infection play a key role in inflammasome formation, suggesting a crucial link between HIV and a chronic inflammatory state. This review outlines the inflammatory processes triggered by HIV-1 infection and aging, with a focus on the inflammasomes. This review also explores current research regarding inflammasomes and potential strategies for targeting inflammasomes to mitigate inflammation. Further research on inflammasome signaling presents a unique opportunity to develop targeted interventions and innovative therapeutic modalities for combating HIV and aging-associated inflammatory processes.

Role of CD4+ T-cells for regulating splenic myelopoiesis and monocyte differentiation after experimental myocardial infarction

Myocardial infarction (MI) induces the generation of proinflammatory Ly6Chigh monocytes in the spleen and the recruitment of these cells to the myocardium. CD4+ Foxp3+ CD25+ T-cells (Tregs) promote the healing process after myocardial infarction by engendering a pro-healing differentiation state in myocardial monocyte-derived macrophages. We aimed to study the effects of CD4+ T-cells on splenic myelopoiesis and monocyte differentiation. We instigated MI in mice and found that MI-induced splenic myelopoiesis is abrogated in CD4+ T-cell deficient animals. Conventional CD4+ T-cells promoted myelopoiesis in vitro by cell-cell-contact and paracrine mechanisms, including interferon-gamma (IFN-γ) signalling. Depletion of regulatory T-cells enhanced myelopoiesis in vivo, as evidenced by increases in progenitor cell numbers and proliferative activity in the spleen 5 days after MI. The frequency of CD4+ T-cells-producing factors that promote myelopoiesis increased within the spleen of Treg-depleted mice. Moreover, depletion of Tregs caused a proinflammatory bias in splenic Ly6Chigh monocytes, which showed predominantly upregulated expression of IFN-γ responsive genes after MI. Our results indicate that conventional CD4+ T-cells promote and Tregs attenuate splenic myelopoiesis and proinflammatory differentiation of monocytes.

Study on the combined toxicity of DEHP and lead on the blood system of rats

Di(2-ethylhexyl) phthalate (DEHP) is a commonly used phthalate ester compound, while lead is a persistent and bioaccumulative heavy metal. Both can be exposed to the body through a variety of ways, which may have an impact on the blood system. In this study, we examined the impact of co-exposure to DEHP (0, 10, 100 mg/kg) and Pb (0, 5, 50 mg/kg) on the blood system of male SD rats. The study revealed that continuous exposure to DEHP and Pb for 20 days resulted in a decrease in leukocytes and lymphocytes, while an increase in neutrophils and monocytes. Co-exposure led to a significant decrease in the spleen coefficients. Furthermore, the combined exposure could increase the ratio of bone marrow cells in G1 phase, and decrease the ratio of cells in S phase and G2 phase. Cytokine testing showed that combined exposure affects the secretion of hematopoietic factors and may cause bone marrow cell apoptosis. Single or combined exposure to DEHP and Pb can cause oxidative stress in serum and bone marrow. Overall, these results indicate that the co-exposure of DEHP and Pb adversely affected the blood system of rats, mainly due to the induction of oxidative stress and ultimately affects the secretion of cytokines. The combined effect of the two substances is primarily antagonistic. These results have important implications for the risk assessment of combined pollution and provide valuable theoretical guidance.

Targeting CD38/ ADP-ribosyl cyclase as a novel therapeutic strategy for identification of three potent agonists for leukopenia treatment

Leukopenia is the most common side effect of chemotherapy and radiotherapy. It potentially deteriorates into a life-threatening complication in cancer patients. Despite several agents being approved for clinical administration, there are still high incidences of pathogen-related disease due to a lack of functional immune cells. ADP-ribosyl cyclase of CD38 displays a regulatory effect on leukopoiesis and the immune system. To explore whether the ADP-ribosyl cyclase was a potential therapeutic target of leukopenia. We established a drug screening model based on an ADP-ribosyl cyclase-based pharmacophore generation algorithm and discovered three novel ADP-ribosyl cyclase agonists: ziyuglycoside II (ZGSII), brevifolincarboxylic acid (BA), and 3,4-dihydroxy-5-methoxybenzoic acid (DMA). Then, in vitro experiments demonstrated that these three natural compounds significantly promoted myeloid differentiation and antibacterial activity in NB4 cells. In vivo, experiments confirmed that the compounds also stimulated the recovery of leukocytes in irradiation-induced mice and zebrafish. The mechanism was investigated by network pharmacology, and the top 12 biological processes and the top 20 signaling pathways were obtained by intersecting target genes among ZGSII, BA, DMA, and leukopenia. The potential signaling molecules involved were further explored through experiments. Finally, the ADP-ribosyl cyclase agonists (ZGSII, BA, and DMA) has been found to regenerate microbicidal myeloid cells to effectively ameliorate leukopenia-associated infection by activating CD38/ADP-ribosyl cyclase-Ca2+-NFAT. In summary, this study constructs a drug screening model to discover active compounds against leukopenia, reveals the critical roles of ADP-ribosyl cyclase in promoting myeloid differentiation and the immune response, and provides a promising strategy for the treatment of radiation-induced leukopenia.

Characterizing ligand-receptor interactions and unveiling the pro-tumorigenic role of CCL16-CCR1 axis in the microenvironment of hepatocellular carcinoma

Background

The heterogeneity of the tumor microenvironment significantly influences the prognosis of hepatocellular carcinoma (HCC) patients, with cell communication through ligand-receptor complexes playing a central role.

Methods

We conducted single-cell transcriptomic analysis on ten HCC tissues to identify ligand-receptor genes involved in malignant HCC cell communication using CellChat. Leveraging RNA-Seq data from the TCGA Liver Cancer (TCGA-LIHC) and Liver Cancer - RIKEN, JP (LIRI-JP) cohorts, we employed Cox regression analysis to screen for prognosis-related genes. Prognostic risk models were constructed through unsupervised clustering and differential gene expression analysis. Subsequently, a co-culture system involving tumor cells and macrophages was established. A series of experiments, including Transwell assays, immunofluorescence staining, immunoprecipitation, flow cytometry, and immunohistochemistry, were conducted to elucidate the mechanism through which HCC cells recruit macrophages via the CCL16-CCR1 axis.

Results

Single-cell analysis unveiled significant interactions between malignant HCC cells and macrophages, identifying 76 related ligand-receptor genes. Patients were classified into three subtypes based on the expression patterns of eight prognosis-related ligand-receptor genes. The subtype with the worst prognosis exhibited reduced infiltration of T cell-related immune cells, downregulation of immune checkpoint genes, and increased M2-like tumor-associated macrophage scores. In vitro experiments confirmed the pivotal role of the CCL16-CCR1 axis in the recruitment and M2 polarization of tumor-associated macrophages. Clinical samples demonstrated a significant association between CCL16 protein expression levels and advanced stage, lymph node metastasis, and distant metastasis. Immunohistochemistry and immunofluorescence staining further confirmed the correlation between CCL16 and CCR1, CD68, and CD206, as well as CD68+CCR1+ macrophage infiltration.

Conclusions

Our study identified molecular subtypes, a prognostic model, and immune microenvironment features based on ligand-receptor interactions in malignant HCC cell communication. Moreover, we revealed the pro-tumorigenic role of HCC cells in recruiting M2-like tumor-associated macrophages through the CCL16-CCR1 axis.

Inflammation and aging: signaling pathways and intervention therapies

Aging is characterized by systemic chronic inflammation, which is accompanied by cellular senescence, immunosenescence, organ dysfunction, and age-related diseases. Given the multidimensional complexity of aging, there is an urgent need for a systematic organization of inflammaging through dimensionality reduction. Factors secreted by senescent cells, known as the senescence-associated secretory phenotype (SASP), promote chronic inflammation and can induce senescence in normal cells. At the same time, chronic inflammation accelerates the senescence of immune cells, resulting in weakened immune function and an inability to clear senescent cells and inflammatory factors, which creates a vicious cycle of inflammation and senescence. Persistently elevated inflammation levels in organs such as the bone marrow, liver, and lungs cannot be eliminated in time, leading to organ damage and aging-related diseases. Therefore, inflammation has been recognized as an endogenous factor in aging, and the elimination of inflammation could be a potential strategy for anti-aging. Here we discuss inflammaging at the molecular, cellular, organ, and disease levels, and review current aging models, the implications of cutting-edge single cell technologies, as well as anti-aging strategies. Since preventing and alleviating aging-related diseases and improving the overall quality of life are the ultimate goals of aging research, our review highlights the critical features and potential mechanisms of inflammation and aging, along with the latest developments and future directions in aging research, providing a theoretical foundation for novel and practical anti-aging strategies.

STAT3 protects HSCs from intrinsic interferon signaling and loss of long-term blood-forming activity

STAT3 function in hematopoietic stem and progenitor cells (HSPCs) has been difficult to discern as Stat3 deficiency in the hematopoietic system induces systemic inflammation, which can impact HSPC activity. To address this, we established mixed bone marrow (BM) chimeric mice with CreER-mediated Stat3 deletion in 20% of the hematopoietic compartment. Stat3-deficient HSPCs had impaired hematopoietic activity and failed to undergo expansion in BM in contrast to Stat3-sufficient (CreER) controls. Single-cell RNA sequencing of Lin-ckit+Sca1+ BM cells revealed altered transcriptional responses in Stat3-deficient hematopoietic stem cells (HSCs) and multipotent progenitors, including intrinsic activation of cell cycle, stress response, and interferon signaling pathways. Consistent with their deregulation, Stat3-deficient Lin-ckit+Sca1+ cells accumulated γH2AX over time. Following secondary BM transplantation, Stat3-deficient HSPCs failed to reconstitute peripheral blood effectively, indicating a severe functional defect in the HSC compartment. Our results reveal essential roles for STAT3 in HSCs and suggest the potential for using targeted synthetic lethal approaches with STAT3 inhibition to remove defective or diseased HSPCs.

Zebrafish: a convenient tool for myelopoiesis research

Myelopoiesis is the process in which the mature myeloid cells, including monocytes/macrophages and granulocytes, are developed. Irregular myelopoiesis may cause and deteriorate a variety of hematopoietic malignancies such as leukemia. Myeloid cells and their precursors are difficult to capture in circulation, let alone observe them in real time. For decades, researchers had to face these difficulties, particularly in in-vivo studies. As a unique animal model, zebrafish possesses numerous advantages like body transparency and convenient genetic manipulation, which is very suitable in myelopoiesis research. Here we review current knowledge on the origin and regulation of myeloid development and how zebrafish models were applied in these studies.

The mechanisms and cross-protection of trained innate immunity

In recent years, the traditional cognition of immunological memory being specific to adaptive immunity has been challenged. Innate immunity can mount enhanced responsiveness upon secondary stimulation, and a phenomenon is termed trained innate immunity. Trained innate immunity is orchestrated by distinct metabolic and epigenetic reprogramming in both circulating myeloid cells and myeloid progenitor cells in bone marrow, leading to long-term resistance to related and non-related pathogens infections. The induction of trained innate immunity can also polarize innate immune cells towards a hyperresponsive phenotype in the tumor microenvironment to exert antitumor effects. This review will discuss the current understanding of innate immune memory and the mechanisms during the induction of innate immunity, including signaling pathways, metabolic changes, and epigenetic rewriting. We also provide an overview of cross-protection against infectious diseases and cancers based on trained innate immunity.

TLR2-induced CD8+ T-cell deactivation shapes dendritic cell differentiation in the bone marrow during sepsis

Sepsis is associated with profound immune dysregulation that increases the risk for life-threatening secondary infections: Dendritic cells (DCs) undergo functional reprogramming due to yet unknown changes during differentiation in the bone marrow (BM). In parallel, lymphopenia and exhaustion of T lymphocytes interfere with antigen-specific adaptive immunity. We hypothesized that there exists a link between T cells and the modulation of DC differentiation in the BM during murine polymicrobial sepsis. Sepsis was induced by cecal ligation and puncture (CLP), a model for human bacterial sepsis. At different time points after CLP, the BM and spleen were analyzed in terms of T-cell subpopulations, activation, and Interferon (IFN)-γ synthesis as well as the number of pre-DCs. BM-derived DCs were generated in vitro. We observed that naïve and virtual memory CD8⁺ T cells, but not CD4⁺ T cells, were activated in an antigen-independent manner and accumulated in the BM early after CLP, whereas lymphopenia was evident in the spleen. The number of pre-DCs strongly declined during acute sepsis in the BM and almost recovered by day 4 after CLP, which required the presence of CD8⁺ T cells. Adoptive transfer experiments and in vitro studies with purified T cells revealed that Toll-like receptor 2 (TLR2) signaling in CD8⁺ T cells suppressed their capacity to secrete IFN-γ and was sufficient to change the transcriptome of the BM during sepsis. Moreover, the diminished IFN-γ production of CD8⁺ T cells favored the differentiation of DCs with increased production of the immune-activating cytokine Interleukin (IL)-12. These data identify a novel role of CD8⁺ T cells in the BM during sepsis as they sense TLR2 ligands and control the number and function of de novo differentiating DCs.

Clonal haematopoiesis is associated with higher mortality in patients with cardiogenic shock

AIMS

Cardiogenic shock (CS) with variable systemic inflammation may be responsible for the patient heterogeneity and the exceedingly high mortality rate. Cardiovascular events have been associated with clonal haematopoiesis (CH) where specific gene mutations in hematopoietic stem cells lead to clonal expansion and the development of inflammation. This study aims to assess the prevalence of CH and its association with survival in a population of CS patients in a quaternary center.

METHODS

We compared the frequency of CH mutations among 341 CS patients and 345 ambulatory heart failure (HF) matched for age, sex, ejection fraction, and HF aetiology. The association of CH with survival and levels of circulating inflammatory cytokines was analysed.

RESULTS

We detected 266 CH mutations in 149 of 686 (22%) patients. CS patients had a higher prevalence of CH-related mutations than HF patients (OR 1.5; 95% CI 1.0-2.1, P=0.02) and was associated with decreased survival (30-days: HR 2.7; 95% CI 1.3-5.7, P=0.006; 90-days: HR 2.2; 95% CI 1.3-3.9, P=0.003; and 3-years: HR 1.7; 95% CI 1.1-2.8, P=0.01). TET2 or ASXL1 mutations were associated with lower survival in CS patients at all-time points (P≤0.03). CS patients with TET2 mutations had higher circulating levels of SCD40L, IFNγ, IL-4, and TNFα (P≤0.04), while those with ASXL1 mutations had decreased levels of CCL7 (P=0.03).

CONCLUSIONS

CS patients have high frequency of CH, notably mutations in TET2 and ASXL1. This was associated with reduced survival and dysregulation of circulating inflammatory cytokines in those CS patients with CH. This article is protected by copyright. All rights reserved.

Inflammation Regulates Haematopoietic Stem Cells and Their Niche

Haematopoietic stem cells (HSCs) reside in the bone marrow and are supported by the specialised microenvironment, a niche to maintain HSC quiescence. To deal with haematopoietic equilibrium disrupted during inflammation, HSCs are activated from quiescence directly and indirectly to generate more mature immune cells, especially the myeloid lineage cells. In the process of proliferation and differentiation, HSCs gradually lose their self-renewal potential. The extensive inflammation might cause HSC exhaustion/senescence and malignant transformation. Here, we summarise the current understanding of how HSC functions are maintained, damaged, or exhausted during acute, prolonged, and pathological inflammatory conditions. We also highlight the inflammation-altered HSC niche and its impact on escalating the insults on HSCs.

Identification of Key Genes Associated with Endothelial Cell Dysfunction in Atherosclerosis Using Multiple Bioinformatics Tools

Atherosclerosis is the most notable cardiovascular disease, the latter being the main cause of death globally. Endothelial cell dysfunction plays a major role in the pathogenesis of atherosclerosis. However, it is currently unclear which genes are involved between endothelial cell dysfunction and atherosclerosis. This study was aimed at identifying these genes. Based on the GSE83500 dataset, the quantification of endothelial cell function was conducted using single-sample gene set enrichment analysis; the coexpression modules were conducted using weighted correlation network analysis. After building module-trait relationships, tan and yellow modules were regarded as hub modules. 10 hub genes from each hub module were identified by the protein-protein interaction network analysis. The key genes (RAB5A, CTTN, ITGB1, and MMP9) were obtained by comparing the expression differences of the hub gene between atherosclerotic and normal groups from the GSE28829 and GSE43292 datasets, respectively. ROC analysis showed the diagnostic value of key genes. Moreover, the differential expression of key genes in normal and atherosclerotic aortic walls was verified. In vitro, we establish a model of ox-LDL-injured endothelial cells and transfect RAB5A overexpression and shRNA plasmids. The results showed that overexpression of RAB5A ameliorates the proliferation and migration function of ox-LDL-injured endothelial cells, including the ability of tubule formation. It was speculated that the interferon response, Notch signaling pathways, etc. were involved in this function of RAB5A by using gene set variation analysis. With the multiple bioinformatics analysis methods, we detected that yellow and tan modules are related to the abnormal proliferation and migration of endothelial cells associated with atherosclerosis. RAB5A, CTTN, ITGB1, and MMP9 can be used as potential targets for therapy and diagnostic markers. In vitro, overexpression of RAB5A can ameliorate the proliferation and migration function of ox-LDL-injured endothelial cells, and the possible molecules involved in this process were speculated.

Open‐Label Pilot Study of Interferon Gamma ‐ 1b in Patients with Non‐infantile Osteopetrosis

The only treatment currently available for patients with severe infantile osteopetrosis is hematopoietic cell transplantation (HCT). HCT‐related toxicity and mortality risks typically preclude its use in non‐infantile patients, and other therapies are needed for these patients who have significant disease‐related morbidity. Interferon gamma‐1b is currently approved by the U.S. Food and Drug Administration (FDA) for treatment of severe infantile osteopetrosis (autosomal recessive osteopetrosis [ARO]). However, little is known about the effects of interferon gamma‐1b in non‐infantile osteopetrosis. Thus, this pilot study aimed at testing the safety and tolerability of interferon gamma‐1b in patients with non‐infantile osteopetrosis and assessing the clinical effects. We performed a 12‐month, open‐label, multi‐center pilot study involving patients >1 year‐old diagnosed radiographically with osteopetrosis. Patients were initiated on interferon gamma‐1b subcutaneously 15 μg/m² three times weekly, to be titrated over 3 weeks to a goal of 100 μg/m² three times weekly. The primary aim was safety and tolerability. The secondary aims were to assess changes in peripheral quantitative computed tomography (pQCT), dual‐energy x‐ray absorptiometry (DXA) bone mineral density (BMD) Z‐scores, bone biomarkers, and quality‐of‐life (QOL) measures. Four of the five participants enrolled withdrew from the study between 3 and 9 months due to intolerability of interferon gamma‐1b–related flu‐like symptoms. The last participant completed the study with the addition of prednisone on days of interferon gamma‐1b administration. DXA and pQCT outcomes were stable over 6–12 months, and there were no clear trends in bone biomarkers or QOL measures. No serious drug‐related adverse events were reported during this study. Interferon gamma‐1b was only tolerable in one of five participants with the addition of prednisone. The stabilization of BMD and other measures of bone health during this study suggest possible positive effects of interferon gamma‐1b on osteopetrosis; however, additional data are needed before conclusions on treatment efficacy can be made. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Inflammation, Aging and Hematopoiesis: A Complex Relationship

All vertebrate blood cells descend from multipotent hematopoietic stem cells (HSCs), whose activity and differentiation depend on a complex and incompletely understood relationship with inflammatory signals. Although homeostatic levels of inflammatory signaling play an intricate role in HSC maintenance, activation, proliferation, and differentiation, acute or chronic exposure to inflammation can have deleterious effects on HSC function and self-renewal capacity, and bias their differentiation program. Increased levels of inflammatory signaling are observed during aging, affecting HSCs either directly or indirectly via the bone marrow niche and contributing to their loss of self-renewal capacity, diminished overall functionality, and myeloid differentiation skewing. These changes can have significant pathological consequences. Here, we provide an overview of the current literature on the complex interplay between HSCs and inflammatory signaling, and how this relationship contributes to age-related phenotypes. Understanding the mechanisms and outcomes of this interaction during different life stages will have significant implications in the modulation and restoration of the hematopoietic system in human disease, recovery from cancer and chemotherapeutic treatments, stem cell transplantation, and aging.

The effect of inflammatory factors and their inhibitors on the hematopoietic stem cells fate

Inflammatory cytokines exert different effects on hematopoietic stem cells (HSCs), lead to the development of various cell lineages in bone marrow (BM) and are thus a differentiation axis for HSCs. The content used in this article has been obtained by searching PubMed database and Google Scholar search engine of English-language articles (1995-2020) using "Hematopoietic stem cell," "Inflammatory cytokine," "Homeostasis," and "Myelopoiesis." Inflammatory cytokines are involved in the differentiation and proliferation of hematopoietic progenitors to compensate for cellular death due to inflammation. Since each of these cytokines differentiates HSCs into a specific cell line, the difference in the effect of these cytokines on the fate of HSC progenitors can be predicted. Inhibitors of these cytokines can also control the inflammatory process as well as the cells involved in leukemic conditions. In general, inflammatory signaling can specify the dominant cell line in BM to counteract inflammation and leukemic condition via stimulating or inhibiting hematopoietic progenitors. Therefore, detection of the effects of inflammatory cytokines on the differentiation of HSCs can be an appropriate approach to check inflammatory and leukemic conditions and the suppression of these cytokines by their inhibitors allows for control of homeostasis in stressful conditions.

Acute Intestinal Inflammation Depletes/Recruits Histamine-Expressing Myeloid Cells From the Bone Marrow Leading to Exhaustion of MB-HSCs

BACKGROUND & AIMS

Histidine decarboxylase (HDC), the histamine-synthesizing enzyme, is expressed in a subset of myeloid cells but also marks quiescent myeloid-biased hematopoietic stem cells (MB-HSCs) that are activated upon myeloid demand injury. However, the role of MB-HSCs in dextran sulfate sodium (DSS)-induced acute colitis has not been addressed.

METHODS

We investigated HDC+ MB-HSCs and myeloid cells by flow cytometry in acute intestinal inflammation by treating HDC-green fluorescent protein (GFP) male mice with 5% DSS at various time points. HDC+ myeloid cells in the colon also were analyzed by flow cytometry and immunofluorescence staining. Knockout of the HDC gene by using HDC-/-; HDC-GFP and ablation of HDC+ myeloid cells by using HDC-GFP; HDC-tamoxifen-inducible recombinase Cre system; diphtheria toxin receptor (DTR) mice was performed. The role of H2-receptor signaling in acute colitis was addressed by treatment of DSS-treated mice with the H2 agonist dimaprit dihydrochloride. Kaplan-Meier survival analysis was performed to assess the effect on survival.

RESULTS

In acute colitis, rapid activation and expansion of MB-HSC from bone marrow was evident early on, followed by a gradual depletion, resulting in profound HSC exhaustion, accompanied by infiltration of the colon by increased HDC+ myeloid cells. Knockout of the HDC gene and ablation of HDC+ myeloid cells enhance the early depletion of HDC+ MB-HSC, and treatment with H2-receptor agonist ameliorates the depletion of MB-HSCs and resulted in significantly increased survival of HDC-GFP mice with acute colitis.

CONCLUSIONS

Exhaustion of bone marrow MB-HSCs contributes to the progression of DSS-induced acute colitis, and preservation of quiescence of MB-HSCs by the H2-receptor agonist significantly enhances survival, suggesting the potential for therapeutic utility.

Classification of four distinct osteoarthritis subtypes with a knee joint tissue transcriptome atlas

The limited molecular classifications and disease signatures of osteoarthritis (OA) impede the development of prediagnosis and targeted therapeutics for OA patients. To classify and understand the subtypes of OA, we collected three types of tissue including cartilage, subchondral bone, and synovium from multiple clinical centers and constructed an extensive transcriptome atlas of OA patients. By applying unsupervised clustering analysis to the cartilage transcriptome, OA patients were classified into four subtypes with distinct molecular signatures: a glycosaminoglycan metabolic disorder subtype (C1), a collagen metabolic disorder subtype (C2), an activated sensory neuron subtype (C3), and an inflammation subtype (C4). Through ligand-receptor crosstalk analysis of the three knee tissue types, we linked molecular functions with the clinical symptoms of different OA subtypes. For example, the Gene Ontology functional term of vasculature development was enriched in the subchondral bone-cartilage crosstalk of C2 and the cartilage-subchondral bone crosstalk of C4, which might lead to severe osteophytes in C2 patients and apparent joint space narrowing in C4 patients. Based on the marker genes of the four OA subtypes identified in this study, we modeled OA subtypes with two independent published RNA-seq datasets through random forest classification. The findings of this work contradicted traditional OA diagnosis by medical imaging and revealed distinct molecular subtypes in knee OA patients, which may allow for precise diagnosis and treatment of OA.

Protective Effects of Biscoclaurine Alkaloids on Leukopenia Induced by 60Co-γ Radiation

Objective

Leukopenia, a common complication of tumor chemoradiotherapy, contributes serious damage to the hematopoietic, gastrointestinal, and immune systems of the body and can cause delay, discontinuation, or even failure to tumor treatment, thereby greatly threatening human health. The present study aims to investigate the protective effects of biscoclaurine alkaloids (BA) on leukopenia.

Methods

This study was conducted on 60 Kunming mice, which were randomly divided into six groups containing 10 animals each. A hematology analyzer was used to count white blood cells (WBC) in the peripheral blood cell. Mice serum was collected, and the granulocyte-macrophage colony-stimulating factor, vascular cell adhesion molecule 1 (VCAM-1), and interferon-γ (IFN-γ) were detected by enzyme-linked immunosorbent assays. Pathological changes were detected through hematoxylin and eosin staining in the liver and spleen of mice. The spleen and liver ultrastructures were observed via electron microscopy.

Results

Results showed that BA ameliorated WBC, PLT reduction in the peripheral blood and significantly increased the levels of IFN-γ and VCAM-1 in mice serum. BA reduced ionizing radiation-induced injuries to spleen, mitigated the reduction of superoxide dismutase (SOD), and significantly decreased the malonaldehyde (MDA) and xanthine oxidase (XOD) levels in the liver.

Conclusion

BA enhanced the immune and hematopoietic functions and ameliorated the oxidative stress induced by ⁶⁰Co-γ radiation, revealing its therapeutic potential both as a radioprotector and as a radiation mitigator for leukopenia induced by ⁶⁰Co-γ radiation.

The Snakeskin-Mesh Complex of Smooth Septate Junction Restricts Yorkie to Regulate Intestinal Homeostasis in Drosophila

Tight junctions in mammals and septate junctions in insects are essential for epithelial integrity. We show here that, in the Drosophila intestine, smooth septate junction proteins provide barrier and signaling functions. During an RNAi screen for genes that regulate adult midgut tissue growth, we found that loss of two smooth septate junction components, Snakeskin and Mesh, caused a hyperproliferation phenotype. By examining epitope-tagged endogenous Snakeskin and Mesh, we demonstrate that the two proteins are present in the cytoplasm of differentiating enteroblasts and in cytoplasm and septate junctions of mature enterocytes. In both enteroblasts and enterocytes, loss of Snakeskin and Mesh causes Yorkie-dependent expression of the JAK-STAT pathway ligand Upd3, which in turn promotes proliferation of intestinal stem cells. Snakeskin and Mesh form a complex with each other, with other septate junction proteins and with Yorkie. Therefore, the Snakeskin-Mesh complex has both barrier and signaling function to maintain stem cell-mediated tissue homeostasis.

•

Snakeskin and Mesh are septate junction proteins essential for intestinal homeostasis

•

Snakeskin and Mesh act in enteroblasts and enterocytes to regulate stem cell division

•

Snakeskin and Mesh form a complex with and restrict the activity of Yorkie

•

Loss of Snakeskin and Mesh allows Yorkie to promote Upd3 expression and growth

The combination of Radix Astragali and Radix Angelicae Sinensis attenuates the IFN-γ-induced immune destruction of hematopoiesis in bone marrow cells

BACKGROUND

Radix Astragali and Radix Angelicae Sinensis are two herbs that compose Danggui Buxue Tang (an herbal formula for treatment of anemia diseases). In this study, we explored the molecular mechanism and effective targets to immune destruction of bone marrow (BM) cells treated with Radix Astragali, Radix Angelicae Sinensis or a combination of two agents. The potential synergic advantages of two herbs should also be explored.

METHODS

The constituents of Radix Astragali and Radix Angelicae Sinensis were analyzed by high performance liquid chromatography-electrospray ionization/mass spectrometer system BM cells were separated from limbs of BALB/c mice, and immune destruction was induced with IFN-γ. The percentages of hematopoietic stem cells (HSCs) and CD3⁺ T cells were detected by flow cytometry. The distribution of T-bet and changes in the combination of SAP and SLAM in BM cells were observed by immunofluorescence. Western blotting was used to assay the expression of key molecules of the eIF2 signaling pathway in BM cells.

RESULTS

Seven constituents of Radix Astragali and six constituents of Radix Angelicae Sinensis were identified. The percentages of HSCs increased significantly after treatment with Radix Angelicae Sinensis, especially at high concentrations. The percentages of CD3⁺ T cells were significantly decreased after Radix Astragali and Radix Angelicae Sinensis treatment. However, the synergistic function of two-herb combinations was superior to that of the individual herbs alone. The distribution of T-bet in BM cells was decreased significantly after Radix Angelicae Sinensis treatment. The number of SLAM/SAP double-stained cells was increased significantly after Radix Astragali treatment at low concentrations. The phosphorylation levels of eIF2α were also reduced after Radix Astragali and Radix Angelicae Sinensis treatment.

CONCLUSIONS

Radix Astragali and Radix Angelicae Sinensis could intervene in the immunologic balance of T lymphocytes, inhibit the apoptosis of BM cells induced by immune attack, restore the balance of the T cell immune response network and recover the hematopoietic function of HSCs. The synergistic effects of Radix Astragali and Radix Angelicae Sinensis were superior to those of each herb alone.

Interferon gamma inhibits the differentiation of mouse adult liver and bone marrow hematopoietic stem cells by inhibiting the activation of notch signaling

BACKGROUND

The paradigm of hematopoietic stem and progenitor cells (HSPCs) has become accepted ever since the discovery of adult mouse liver hematopoietic stem cells and their multipotent characteristics that give rise to all blood cells. However, differences between bone marrow (BM) and liver hematopoietic stem cells and the hematopoietic microenvironment remain poorly understood. In addition, the regulation of the liver hematopoietic system remains unknown.

METHODS

Clone formation assays were used to confirm that the proliferation of adult mouse liver and bone marrow HSPCs. Model mice with different interferon gamma (IFN-γ) levels and a co-culture system were used to detect the differentiation of liver HSPCs. The γ-secretase inhibitor (GSI) and the JAK/STAT inhibitor ruxolitinib and cell culture assays were used to explore the molecular mechanism by which IFN-γ impairs HSPC proliferation and differentiation.

RESULTS

The colony-forming activity of liver and bone marrow HSPCs was inhibited by IFN-γ. Model mice with different IFN-γ levels showed that the differentiation of liver HSPCs was impaired by IFN-γ. Using a co-culture system comprising liver HSPCs, we found that IFN-γ inhibited the development of liver hematopoietic stem cells into γδT cells. We then demonstrated that IFN-γ might impair liver HSPC differentiation by inhibiting the activation of the notch signaling via the JAK/STAT signaling pathway.

CONCLUSIONS

IFN-γ inhibited the proliferation of liver-derived HSPCs. IFN-γ also impaired the differentiation of long-term hematopoietic stem cells (LT-HSCs) into short-term hematopoietic stem cells (ST-HSCs) and multipotent progenitors (MPPs) and the process from LSK (Lineage^-Sca-1⁺c-Kit⁺) cells to γδT cells. Importantly, we proposed that IFN-γ might inhibit the activation of notch signaling through the JAK/STAT signaling pathway and thus impair the differentiation process of mouse adult liver and BM hematopoietic stem cells.

Kupffer Cells Promote the Differentiation of Adult Liver Hematopoietic Stem and Progenitor Cells into Lymphocytes via ICAM-1 and LFA-1 Interaction

It has been reported that the adult liver contains hematopoietic stem and progenitor cells (HSPCs), which are associated with long-term hematopoietic reconstitution activity. Hepatic hematopoiesis plays an important role in the generation of cells involved in liver diseases. However, how the progenitors differentiate into functional myeloid cells and lymphocytes in the liver microenvironment remains unknown. In the present study, HSPC transplantation experiments were used to confirm that adult murine liver HSPCs differentiate into both myeloid cells and lymphocytes (preferentially T cells) compared with bone marrow HSPCs. Using a coculture system comprised of kupffer cells and HSPCs, we found that kupffer cells promote adult liver HSPCs to primarily generate T cells and B cells. We then demonstrated that kupffer cells can also promote HSPC expansion. A blockade of intercellular cell adhesion molecule-1 (ICAM-1) in a liver HSPC and kupffer cell coculture system impaired the adhesion, expansion, and differentiation of HSPCs. These results suggest a critical role of kupffer cells in the maintenance and promotion of adult mouse liver hematopoiesis. These findings provide important insight into understanding liver extramedullary hematopoiesis and its significance, particularly under the state of some liver diseases, such as hepatitis, nonalcoholic fatty liver disease (NAFLD), and hepatocellular carcinoma (HCC).

Deferasirox drives ROS-mediated differentiation and induces interferon-stimulated gene expression in human healthy haematopoietic stem/progenitor cells and in leukemia cells

Background

Administration of the iron chelator deferasirox (DFX) in transfusion-dependent patients occasionally results in haematopoiesis recovery by a mechanism remaining elusive. This study aimed to investigate at a molecular level a general mechanism underlying DFX beneficial effects on haematopoiesis, both in healthy and pathological conditions.

Methods

Human healthy haematopoietic stem/progenitor cells (HS/PCs) and three leukemia cell lines were treated with DFX. N-Acetyl cysteine (NAC) and fludarabine were added as antioxidant and STAT1 inhibitor, respectively. In vitro colony-forming assays were assessed both in healthy and in leukemia cells. Intracellular and mitochondrial reactive oxygen species (ROS) as well as mitochondrial content were assessed by cytofluorimetric and confocal microscopy analysis; mtDNA was assessed by qRT-PCR. Differentiation markers were monitored by cytofluorimetric analysis. Gene expression analysis (GEA) was performed on healthy HS/PCs, and differently expressed genes were validated in healthy and leukemia cells by qRT-PCR. STAT1 expression and phosphorylation were assessed by Western blotting. Data were compared by an unpaired Student t test or one-way ANOVA.

Results

DFX, at clinically relevant concentrations, increased the clonogenic capacity of healthy human CD34⁺ HS/PCs to form erythroid colonies. Extension of this analysis to human-derived leukemia cell lines Kasumi-1, K562 and HL60 confirmed DFX capacity to upregulate the expression of specific markers of haematopoietic commitment. Notably, the abovementioned DFX-induced effects are all prevented by the antioxidant NAC and accompanied with overproduction of mitochondria-generated reactive oxygen species (ROS) and increase of mitochondrial content and mtDNA copy number. GEA unveiled upregulation of genes linked to interferon (IFN) signalling and tracked back to hyper-phosphorylation of STAT1. Treatment of leukemic cell lines with NAC prevented the DFX-mediated phosphorylation of STAT1 as well as the expression of the IFN-stimulated genes. However, STAT1 inhibition by fludarabine was not sufficient to affect differentiation processes in leukemic cell lines.

Conclusions

These findings suggest a significant involvement of redox signalling as a major regulator of multiple DFX-orchestrated events promoting differentiation in healthy and tumour cells. The understanding of molecular mechanisms underlying the haematological response by DFX would enable to predict patient’s ability to respond to the drug, to extend treatment to other patients or to anticipate the treatment, regardless of the iron overload.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1293-y) contains supplementary material, which is available to authorized users.

Dehydroepiandrosterone stimulates inflammation and impairs ovarian functions of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility in child-bearing-age women. It is characterized by ovulation dysfunction, polycystic ovaries, and hyperandrogenism. Inflammation is likely to be a crucial contributor to the pathogenesis of PCOS. However, the association between the inflammatory cytokines and the development of PCOS has not been reported. To explore the relationship between the inflammatory cytokines and PCOS, alterations of serum proteins in dehydroepiandrosterone (DHEA)-induced PCOS rats were screened by protein array, and the concentration of IFN-γ was further measured by using enzyme-linked immunosorbent assay (ELISA). DHEA-induced PCOS rats had a decreased level of IFN-γ compared with the control rats, which was restored partly in flutamide (an androgen receptor antagonist)-treated rats. Moreover, the level of IFN-γ in serum of patients with PCOS was also lower than that in healthy women. Using the ovarian granulosa cells (KGN), we demonstrated that DHEA downregulated the expression and secretion of IFN-γ in dose- and time-dependent manners, which could be restored to some extent by treating with flutamide. Furthermore, flutamide ameliorated the inhibitory effect on cell proliferation and promotive effect on cell apoptosis by DHEA. The results also revealed that IFN-γ promoted the proliferation but inhibited the apoptosis of KGN cells, which was suppressed by DHEA via activating the downstream PI3K/AKT signaling pathway. Taken together, these results showed that DHEA inhibited the proliferation and promoted the apoptosis of ovarian granulosa cells through downregulating the expression of IFN-γ which could be restored by flutamide, and IFN-γ may serve as a potential inflammatory biomarker for PCOS detection.

Nystatin enhances the immune response against Candida albicans and protects the ultrastructure of the vaginal epithelium in a rat model of vulvovaginal candidiasis

Background

Vulvovaginal candidiasis (VVC) is a common infectious disease of the lower genital tract. Nystatin, a polyene fungicidal antibiotic, is used as a topical antifungal agent for VVC treatment. The aim of the current study was to investigate the possible immunomodulatory effects of nystatin on the vaginal mucosal immune response during Candida albicans infection and examine its role in protection of vaginal epithelial cell (VEC) ultrastructure.

Results

Following infection with C. albicans, IFN-γ and IL-17 levels in VECs were significantly elevated, while the presence of IgG was markedly decreased as compared to uninfected controls (P <  0.05). No significant differences in IL4 expression were observed. After treatment with nystatin, the level of IFN-γ, IL-17 and IgG was dramatically increased in comparison to the untreated group (P <  0.05). Transmission electron microscopy revealed that C. albicans invades the vaginal epithelium by both induced endocytosis and active penetration. Nystatin treatment protects the ultrastructure of the vaginal epithelium. Compared with the untreated C. albicans-infected group, Flameng scores which measure mitochondrial damage of VECs were markedly decreased (P <  0.001) and the number of adhesive and invasive C. albicans was significantly reduced (P <  0.01) after treatment with nystatin.

Conclusions

Nystatin plays a protective role in the host defense against C. albicans by up-regulating the IFN-γ-related cellular response, the IL-17 signaling pathway and possibly through enhancing VEC-derived IgG-mediated immunity. Furthermore, nystatin notably improves the ultramorphology of the vaginal mucosa, partially through the protection of mitochondria ultrastructure in VECs and inhibition of adhesion and invasion by C. albicans. Together, these effects enhance the immune response of the vaginal mucosa against C. albicans and protect the ultrastructure of vaginal epithelium in VVC rats.

Estrogen is involved in hemangioma regression associated with mast cells

BACKGROUND

Estrogen plays a role in infantile hemangioma (IH) development, but the underlying mechanism remains unclear. This study aimed to assess estrogen and estrogen receptor (ER) localization and expression levels in IH. In addition, the unexpected relationship between mast cells (MCs) and estrogen in human IH was discussed.

METHODS

IH (n = 29), vascular malformation (VMs, n = 33) and normal skin (n = 15) specimens were assessed. IH was classified into proliferative (n = 9; age, 3.56 ± 1.01 months), early involuting (n = 10; age, 8.90 ± 2.69 months) and late involuting (n = 10; age, 20.10 ± 4.93 months) groups. Estradiol (E2), ER-a, ER-β, and tryptase (MC marker) levels were determined immunohistochemically and/or by double immunofluorescence staining. Quantification and localization of tryptase, ER-a, and E2 were assessed for each specimen.

RESULTS

ER-a, E2, and tryptase were expressed in the cytoplasm and nucleus of MCs in IH. The IH specimens showed significantly more tryptase, ER-a, and E2 positive MCs (30.6 ± 12.7, 9.7 ± 5.6, and 19.8 ± 8.7 cells/high-power field [HPF], respectively) compared with VM specimens (9.0 ± 9.8, 1.5 ± 2.4, and 2.5 ± 4.1 cells/HPF, respectively) and normal skin (6.1 ± 8.5, 0.5 ± 1.2, and 1.9 ± 3.4 cells/HPF, respectively). Proliferating IH displayed fewer E2 positive MCs (14.0 6.3 cells/HPF) compared with early (22.3 ± 10.2 cells/HPF, P = 0.023) and late (22.4 ± 6.8 cells/HPF, P = 0.006) involuting specimens. In addition, proliferating IH showed fewer tryptase positive MCs (24.7 ± 10.8 cells/HPF) compared with early involuting specimens (35.7 ± 15.3 cells/HPF, P = 0.043). All IH specimens were ER-a positive and ER-β negative.

CONCLUSIONS

E2 and ER-a are expressed on MCs and not on IH endothelial cells. Furthermore, activated MCs may be involved in IH regression.

Sarcodon imbricatus polysaccharides improve mouse hematopoietic function after cyclophosphamide-induced damage via G-CSF mediated JAK2/STAT3 pathway

Sarcodon imbricatus, a rare medicinal and edible fungus, has various pharmacological bioactivities. We investigated the effects of S. imbricatus polysaccharides (SIPS) on hematopoietic function and identified the underlying mechanisms using in vitro experiments with CHRF, K562, and bone marrow mononuclear cells (BMMNCs) and in vivo experiments with a mouse model of cyclophosphamide-induced hematopoietic dysfunction. We found that SIPS induced proliferation and differentiation of CHRF and K562 cells and upregulated the expression of hematopoietic-related proteins, including p90 ribosomal S6 kinases (RSK1p90), c-Myc, and ETS transcription factor, in the two cell lines. After 28 days of treatment, SIPS enhanced the bodyweight and thymus indices of the mice, alleviated enlargement of the spleen and liver, and contributed to the recovery of peripheral blood to normal levels. More importantly, the percentages of B lymphocytes and hematopoietic stem cells or hematopoietic progenitor cells were significantly elevated in bone marrow. Based on an antibody chip analysis and enzyme-linked immunosorbent assay, SIPS were found to successfully regulate 12 cytokines to healthy levels in serum and spleen. The cytokines included the following: interleukins 1Ra, 2, 3, 4, 5, and 6, tumor necrosis factor α, interferon⁻γ, granulocyte colony-stimulating factor (G-CSF) and macrophage colony-stimulating factor (M-CSF), C-C motif chemokine1, and monocyte chemoattractant protein⁻1. Moreover, SIPS upregulated the phosphorylation levels of janus kinase 2 (JAK2) and the signal transducer and activator of transcription 3 (STAT3) in the spleen, and similar results were validated in CHRF cells, K562 cells, and BMMNCs. The data indicate that SIPS activated the JAK2/STAT3 pathway, possibly by interactions among multiple cytokines, particularly G-CSF. We found that SIPS was remarkably beneficial to the bone marrow hematopoietic system, and we anticipate that it could improve myelosuppression induced by long-term radiotherapy or chemotherapy.

Prolonged skin grafts survival time by IFN-γ in allogeneic skin transplantation model during acute rejection through IFN-γ/STAT3/IDO pathway in epidermal layer

Allogeneic skin transplantation is the life-saving therapy for multiple diseases, including extensive burn, large-scale trauma and certain post-surgical complications. However, acute rejection impedes clinical application of allogeneic skin transplantation. Although a lot of novel immunosuppressant drugs have been developed, there is still great need for ideal therapy with less complication and more therapeutic effects. Here, we found interferon gamma (IFN-γ) as an immunomodulatory cytokine prolonged the survival time of allografts from (8.50 ± 1.517) days to (14.83 ± 2.714) days at best. Indoleamine-2, 3-dioxygenase (IDO) has been proposed to play key roles in induction of immune tolerance. Using in vitro tissue culture and primary keratinocytes and fibroblasts, we investigated the regulatory effects of IFN-γ on the IDO expression. IFN-γ upregulated IDO expression through STAT3 phosphorylation and this upregulation was reduced by abolition of STAT3 phosphorylation through a STAT3 phosphorylation inhibitor. Interestingly, IFN-γ induced IDO expression predominately in epidermis rather than dermis. In consistent with these results, IFN-γ significantly triggered IDO expression in keratinocytes but not fibroblasts. Taken together, this suggests that IFN-γ might be a potential immunomodulatory drug in acute rejection and keratinocytes in epidermis may play a main role in immune tolerance after allogeneic skin transplantation.