No abstract

Proper functioning of the lymphatic system is required for normal immune responses, fluid balance, and lipid reabsorption. Multiple regulatory mechanisms are employed to ensure the correct formation and function of lymphatic vessels; however, the epigenetic modulators and mechanisms involved in this process are poorly understood. Here, we assess the regulatory role of mouse Dot1l, a histone H3 lysine (K) 79 (H3K79) methyltransferase, in lymphatic formation. Genetic ablation of Dot1l in Tie2(+) endothelial cells (ECs), but not in Lyve1(+) or Prox1(+) lymphatic endothelial cells (LECs) or Vav1(+) definitive hematopoietic stem cells, leads to catastrophic lymphatic anomalies, including skin edema, blood-lymphatic mixing, and underdeveloped lymphatic valves and vessels in multiple organs. Remarkably, targeted Dot1l loss in Tie2(+) ECs leads to fully penetrant lymphatic aplasia, whereas Dot1l overexpression in the same cells results in partially hyperplastic lymphatics in the mesentery. Genetic studies reveal that Dot1l functions in c-Kit(+) hemogenic ECs during mesenteric lymphatic formation. Mechanistically, inactivation of Dot1l causes a reduction of both H3K79me2 levels and the expression of genes important for LEC development and function. Thus, our study establishes that Dot1l-mediated epigenetic priming and transcriptional regulation in LEC progenitors safeguard the proper lymphatic development and functioning of lymphatic vessels.

Mechanistic understanding of germ cell formation at a genome-scale level can aid in developing novel therapeutic strategies for infertility. Germ cell formation is a complex process that is regulated by various mechanisms, including epigenetic regulation, germ cell-specific gene transcription, and meiosis. Gonads contain a limited number of germ cells at various stages of differentiation. Hence, genome-scale analysis of germ cells at the single-cell level is challenging. Conventional genome-scale approaches cannot delineate the landscape of genomic, transcriptomic, and epigenomic diversity or heterogeneity in the differentiating germ cells of gonads. Recent advances in single-cell genomic techniques along with single-cell isolation methods, such as microfluidics and fluorescence-activated cell sorting, have helped elucidate the mechanisms underlying germ cell development and reproductive disorders in humans. In this review, the history of single-cell transcriptomic analysis and their technical advantages over the conventional methods have been discussed. Additionally, recent applications of single-cell transcriptomic analysis for analyzing germ cells have been summarized.

Chronic graft-versus-host disease (cGVHD) remains a major obstacle impeding successful allogeneic hematopoietic cell transplantation (allo-HCT). MicroRNAs (miRs) play key roles in immune regulation during acute GVHD development. Preclinical studies to identify miRs that impact cGVHD pathogenesis are required to develop these as potential life-saving interventions. Using oligonucleotide array, we identified miR-31 that was significantly elevated in allogeneic T cells following HCT in mice. Using genetic and pharmacological approaches, we demonstrated a key role for miR-31 in mediating donor T-cell pathogenicity in cGVHD. Recipients of miR-31-deficient T cells displayed improved cutaneous and pulmonary cGVHD. Deficiency of miR-31 reduced T-cell expansion and Th17 differentiation, but increased generation and function of Tregs. MiR-31 facilitated Neuropilin-1 down-regulation, Foxp3 loss and IFNγ production in alloantigen-induced Tregs. Mechanistically, miR-31 was required for Hypoxia-inducible Factor 1α (HIF1α) upregulation in allogeneic T cells. Hence, miR-31-deficient CD4 T cells displayed impaired activation, survival, Th17 differentiation and glycolytic metabolism under hypoxia. Upregulation of Factor Inhibiting HIF1 (FIH1), a direct target of miR-31, in miR-31-deficient T cells was essential for attenuating T-cell pathogenicity. However, miR-31-deficienty CD8 T cells maintained intact glucose metabolism, cytolytic activity and graft-versus-leukemia response. Importantly, systemic administration of a specific inhibitor of miR-31 effectively reduced donor T-cell expansion, improved Treg generation, and attenuated cGVHD. Taken together, miR-31 is a key driver for T-cell pathogenicity in cGVHD but not for the anti-leukemia activity. Taken together, miR-31 is essential to drive cGVHD pathogenesis and represents a novel potential therapeutic target for controlling cGVHD.

Brief summary: Fli-1 regulates both inflammatory and anti-inflammatory T-cell subsets and can be targeted via available pharmaceutical agents.

Stimulator of interferon genes (STING)-mediated innate immune activation plays a key role in tumor-and self-DNA elicited anti-tumor immunity and autoimmunity, respectively, yet the mechanism remains largely unclear. We utilized murine models of allogeneic hematopoietic cell transplantation (allo-HCT) to study the biology of STING in antigen-presenting cells (APCs) and T cells. STING expression in donor T cells was dispensable for their ability to induce graftversus-host disease (GVHD), a major complication of allo-HCT in the clinic. However, when STING-deficient mice were used as recipients, more severe GVHD was induced after allo-HCT.Using bone marrow (BM) chimeras where STING was absent in different compartments, we found that STING-deficiency on host hematopoietic cells was primarily responsible for exacerbating the disease. Furthermore, STING on host CD11c + cells played a dominant role in the regulation of allogeneic T-cell responses. Mechanistically, STING deficiency resulted in increased survival, activation and function of APCs, including macrophages and dendritic cells (DCs). Consistently, constitutive activation of STING attenuated the survival, activation and function of APCs isolated from STING V154M knock-in mice. In addition, STING-deficient APCs augmented donor T-cell expansion, chemokine receptor expression and migration into intestinal tissues, resulting in accelerated/exacerbated GVHD. Using pharmacologic approaches, we demonstrate that systemic administration of a STING agonist (c-di-GMP) to recipient mice before transplantation significantly reduced GVHD mortality. In conclusion, we reveal a novel role of STING in APC activity that dictates T-cell allogeneic responses and validate STING as a potential therapeutic target for controlling GVHD after allo-HCT.

Muscle fatigue is induced by an acute or chronic physical performance inability after excessive physical activity often associated with lactate accumulation, the end-product of glycolysis. In this study, the water-extracted roots of Sanguisorba officinalis L., a herbal medicine traditionally used for inflammation and diarrhea, reduced the activities of lactate dehydrogenase A (LDHA) in in vitro enzyme assay myoblast C2C12 cells and murine muscle tissue. Physical performance measured by a treadmill test was improved in the S. officinalis-administrated group. The analysis of mouse serum and tissues showed significant changes in lactate levels. Among the proteins related to energy metabolism-related physical performance, phosphorylated-AMP-activated protein kinase alpha (AMPKα) and peroxisome proliferator-activated receptor-coactivator-1 alpha (PGC-1α) levels were enhanced, whereas the amount of LDHA was suppressed. Therefore, S. officinalis might be a candidate for improving physical performance via inhibiting LDHA and glycolysis.

Background : Recently, two commercialized whole-blood assays, QuantiFERON ® -TB Gold (QFT) and T SPOT-TB ® (SPOT), which measure the IFN-γ released in the whole blood after being incubation with mycobacterial antigens, were approved for the diagnosis of a latent tuberculosis infection (LTBI). However, there is data on whether or not the previously used PPD skin tests (TST) have any influence on the diagnostic ability of these ex-vivo IFN-γ assays. Methods : Forty-six 15 year-old students who did not appear to be infected with Mycobacterium tuberculosis were enrolled in this study. The peripheral blood was collected and used for two IFN-γ assays. The IFN-γ assays and TST were performed at the baseline (1 st ). The TST was repeated two months later (2 nd ), and the IFN-γ assays were repeated two (2 nd ) and four months (3 rd ) later only in those subjects who had negative results at the baseline in both the IFN-γ assays and TST. An induration size > 10 mm was considered to be positive in the TST. Results : The mean TST value was 3.1 ± 5.4 mm (range: 0-20). Of the 46 subjects examined, 13 subjects (28.3%) showed positive results in the two-step TST. Nine (19.6%) were SPOT-positive and only one (2.2%) was QFT-positive. The 2 nd and 3 rd QFT were carried out in 23 and 25 all-negative subjects, respectively, and all showed negative results.The 2 nd SPOT was performed in 23 subjects and only one (4.3%) showed a weak-positive result. Conclusion: Even though there were some discrepancies in the results of the two ex-vivo IFN-γ assays, it appears that their results were not influenced by a previous TST carried out in two or four months earlier.