Project description:Patients with myelodysplastic syndromes (MDSs) display severe anemia but the mechanisms underlying this phenotype are incompletely understood. Right open-reading-frame kinase 2 (RIOK2) encodes a protein kinase located at 5q15, a region frequently lost in patients with MDS del(5q). Here we show that hematopoietic cell-specific haploinsufficient deletion of Riok2 (Riok2f/+Vav1cre) led to reduced erythroid precursor frequency leading to anemia. Proteomic analysis of Riok2f/+Vav1cre erythroid precursors suggested immune system activation, and transcriptomic analysis revealed an increase in p53-dependent interleukin (IL)-22 in Riok2f/+Vav1cre CD4+ T cells (TH22). Further, we discovered that the IL-22 receptor, IL-22RA1, was unexpectedly present on erythroid precursors. Blockade of IL-22 signaling alleviated anemia not only in Riok2f/+Vav1cre mice but also in wild-type mice. Serum concentrations of IL-22 were increased in the subset of patients with del(5q) MDS as well as patients with anemia secondary to chronic kidney disease. This work reveals a possible therapeutic opportunity for reversing many stress-induced anemias by targeting IL-22 signaling.
Project description:IBD is a complex autoimmune disease characterized by dysregulated interactions between host immune responses and microbiome at the intestinal epithelium interface. Here we identified shared protein alterations in intestinal epithelial differentiation and function between IBD and Citrobacter rodentium infected FVB mice. We discovered that prophylactic treatment with the mucosal healing therapy IL-22.Fc in the infected FVB mice reduced disease severity and rescued the mice from lethality. Notably, we observed an emergence of intermediate undifferentiated intestinal epithelial cells upon infection, with disrupted expression of the solute transporter machinery as well as components critical for intestinal barrier integrity. Multi-omics analyses revealed that with IL-22.Fc treatment several disease associated changes were prevented (including disruption of the solute transporter machinery), and proper physiological homeostatic functions of the intestine was restored. Taken together, we unveiled the disease relevance of the C. rodentium induced colitis model to IBD and demonstrated the protective role of the mucosal healing therapy IL-22.Fc in ameliorating the epithelial dysfunction.
Project description:Erythropoiesis is a tightly regulated process. Development of red blood cells occurs through differentiation of hematopoietic stem cells into more committed progenitors and finally into erythrocytes. Binding of erythropoietin to its receptor (EpoR) is strictly required for erythropoiesis as it promotes survival and late maturation of erythroid progenitors. In vivo and in vitro studies have highlighted the requirement of EpoR signaling through Jak2 tyrosine-kinase and Stat5a/b as a central pathway. Here, we demonstrate that phospholipase C gamma 1 (Plcγ1) is activated downstream of EpoR/Jak2 independently of Stat5. Plcγ1-deficient proerythroblasts and erythroid progenitors exhibited strong impairment in differentiation and colony-forming potential. In vivo, suppression of Plcγ1 in immunophenotypically defined hematopoietic stem cells (Lin-Sca1+KIT+CD48-CD150+) severely reduced erythroid development. To identify Plcγ1 effector molecules involved in regulation of erythroid differentiation we assessed for changes on the level of transcription and DNA methylation after inactivation of Plcγ1. The single common downstream effector was H2AFY2, which encodes for the histone variant macroH2A2 (mH2A2). Suppression of macroH2A2 expression recapitulated the effects of Plcγ1 knockdown on erythroid maturation. Taken together, our findings identify Plcγ1 and its downstream target macroH2A2, as a ânon-canonicalâ signaling pathway essential for erythroid differentiation. MCIP-seq was used to interrogate methylation changes during Epo-induced differentiation of murine I/11 erythroblastic cell line upon knock-down of Plcy1 as compared to a mock control. Two different shRNA constructs that target Plcg1 were investigated at two different time points.
Project description:Erythropoiesis is a tightly regulated process. Development of red blood cells occurs through differentiation of hematopoietic stem cells into more committed progenitors and finally into erythrocytes. Binding of erythropoietin to its receptor (EpoR) is strictly required for erythropoiesis as it promotes survival and late maturation of erythroid progenitors. In vivo and in vitro studies have highlighted the requirement of EpoR signaling through Jak2 tyrosine-kinase and Stat5a/b as a central pathway. Here, we demonstrate that phospholipase C gamma 1 (Plcγ1) is activated downstream of EpoR/Jak2 independently of Stat5. Plcγ1-deficient proerythroblasts and erythroid progenitors exhibited strong impairment in differentiation and colony-forming potential. In vivo, suppression of Plcγ1 in immunophenotypically defined hematopoietic stem cells (Lin-Sca1+KIT+CD48-CD150+) severely reduced erythroid development. To identify Plcγ1 effector molecules involved in regulation of erythroid differentiation we assessed for changes on the level of transcription and DNA methylation after inactivation of Plcγ1. The single common downstream effector was H2AFY2, which encodes for the histone variant macroH2A2 (mH2A2). Suppression of macroH2A2 expression recapitulated the effects of Plcγ1 knockdown on erythroid maturation. Taken together, our findings identify Plcγ1 and its downstream target macroH2A2, as a “non-canonical” signaling pathway essential for erythroid differentiation.
Project description:BackgroundDelineating the role of microRNAs (miRNAs) in the posttranscriptional gene regulation offers new insights into how the heart adapts to pathological stress. We developed a knockout of miR-22 in mice and investigated its function in the heart.Methods and resultsHere, we show that miR-22-deficient mice are impaired in inotropic and lusitropic response to acute stress by dobutamine. Furthermore, the absence of miR-22 sensitized mice to cardiac decompensation and left ventricular dilation after long-term stimulation by pressure overload. Calcium transient analysis revealed reduced sarcoplasmic reticulum Ca(2+) load in association with repressed sarcoplasmic reticulum Ca(2+) ATPase activity in mutant myocytes. Genetic ablation of miR-22 also led to a decrease in cardiac expression levels for Serca2a and muscle-restricted genes encoding proteins in the vicinity of the cardiac Z disk/titin cytoskeleton. These phenotypes were attributed in part to inappropriate repression of serum response factor activity in stressed hearts. Global analysis revealed increased expression of the transcriptional/translational repressor purine-rich element binding protein B, a highly conserved miR-22 target implicated in the negative control of muscle expression.ConclusionThese data indicate that miR-22 functions as an integrator of Ca(2+) homeostasis and myofibrillar protein content during stress in the heart and shed light on the mechanisms that enhance propensity toward heart failure.
Project description:Rapid expansion of stress erythroid progenitors is a key response to acute anemia during stress erythropoiesis. Besides the rapidly amplifying progenitors, a small population of stem-cell like erythroid progenitors undergoes limited number of cell divisions and maintains their stemness. In this study, we addressed the differences in expression profiles of regulatory genes between two stress erythroid progenitor populations that were identified by proliferation capacity and physiological status. We used microarrays to detail the gene expression profiles of stem-cell like stress erythroid progenitors and rapidly amplifying stress erythroid progenitors during stress erythropoiesis.
Project description:The microtubule-stabilizing agent paclitaxel frequently leads to chemotherapy-induced peripheral neuropathy (CIN), which further increases the burden of disease and often necessitates treatment limitations. The pathophysiology of CIN appears to involve both "upstream" effects including altered intracellular calcium signaling and activation of calcium dependent proteases such as calpain as well as subsequent "downstream" neuro-inflammatory reactions with cytokine release and macrophage infiltration of dorsal root ganglia. In this study, we aimed to investigate whether these processes are linked by the pro-inflammatory cytokine interleukin-6 (IL-6). We observed that paclitaxel exposure induced IL-6 synthesis in cultured sensory neurons from postnatal Wistar rats, which could be prevented by co-treatment with a calpain inhibitor. This suggests a calcium dependent process. We demonstrate that adult C57BL/6 mice deficient in IL-6 are protected from developing functional and histological changes of paclitaxel-induced neuropathy. Furthermore, pretreatment with an IL-6-neutralizing antibody resulted in the prevention of paclitaxel-induced neuropathy in C57BL/6 mice. Electrophysiological data from our preclinical model was adequately reflected by measurements of patients undergoing paclitaxel therapy for ovarian cancer. In this cohort, measured Il-6 levels correlated with the severity of neuropathy. Our findings demonstrate that IL-6 plays a pivotal role in the pathophysiology of paclitaxel-induced neuropathy per se and that pharmacological or genetic interference with this signaling pathway prevents the development of this potentially debilitating adverse effect. These findings provide a rationale for a clinical trial with IL-6 neutralizing antibodies to prevent dose-limiting neurotoxic adverse effects of paclitaxel chemotherapy.
Project description:Uncontrollable inflammatory response acts as a driver of sepsis-associated liver injury (SALI). IL-22 plays an important role in regulating inflammatory responses, but its role in SALI remains unknown. The aim of the study was to assess the association of serum IL-22 with SALI in pediatric patients and to enclose the underlying mechanisms of IL-22 involved in lipopolysaccharide (LPS) - induced acute liver injury (ALI) in mice. Serum IL-22 levels in patients with SALI were significantly lower than in septic patients without liver injury, and the area under receiver operating characteristic (ROC) curve of IL-22 for discriminating SALI was 0.765 (95% CI: 0.593-0.937). Pre-administration of recombinant murine IL-22 alleviated LPS-induced ALI in mice, and serum IL-6 levels and the mRNA levels of TNF-α, IL-1β, and IL-6 in livers were decreased in response to IL-22 pre-treatment in mice. More importantly, IL-22 pre-treatment activated hepatic autophagy mediated by activating transcription factor 4 (ATF4)-autophagy-related gene 7 (ATG7) signaling in vivo and in vitro in response to LPS administration. Moreover, knockdown of ATF4 in mice aggravated LPS-induced ALI, which was associated with suppressed ATG7-related autophagy. In addition, the protective effects of IL-22 on LPS-induced ALI was partially blocked by ATF4 knockdown, which was associated with lower expression of LC3II/I in the livers of ATF4 knockdown (HT or Atf4+/-) mice compared with wild-type mice (WT or Atf4+/+) mice. In conclusion, low serum IL-22 level is associated with SALI occurrence, and IL-22 pre-administration activates autophagy in hepatocytes and protects mice against LPS-induced ALI partially related to ATF4-ATG7 signaling pathway.
Project description:IL-22 is a member of the IL-10 cytokine family involved in host protection against extracellular pathogens, by promoting epithelial cell regeneration and barrier functions. Dysregulation of IL-22 production has also frequently been observed in acute respiratory distress syndrome (ARDS) and several chronic inflammatory and autoimmune diseases. We have previously described that human CD28, a crucial co-stimulatory receptor necessary for full T cell activation, is also able to act as a TCR independent signaling receptor and to induce the expression of IL-17A and inflammatory cytokines related to Th17 cells, which together with Th22 cells represent the main cellular source of IL-22. Here we characterized the role of CD28 autonomous signaling in regulating IL-22 expression in human CD4+ T cells. We show that CD28 stimulation in the absence of TCR strongly up-regulates IL-22 gene expression and secretion. As recently observed for IL-17A, we also found that CD28-mediated regulation of IL-22 transcription requires the cooperative activities of both IL-6-activated STAT3 and RelA/NF-κB transcription factors. CD28-mediated IL-22 production also promotes the barrier functions of epithelial cells by inducing mucin and metalloproteases expression. Finally, by using specific inhibitory drugs, we also identified CD28-associated class 1A phosphatidylinositol 3-kinase (PI3K) as a pivotal mediator of CD28-mediated IL-22 expression and IL-22-dependent epithelial cell barrier functions.