Key Points Abnormal signatures in TGF-β1 signaling gene expression were identified in spleen and marrow from the Gata1low model of MF. These signatures include abnormalities in individual gene (Id2, Stat1, mTOR) in spleen and of gene pathways (Smads and BMPs) in marrow.

Chromogranin A (CgA (CHGA)) is the major soluble protein co-stored and co-released with catecholamines and can function as a pro-hormone by giving rise to several bioactive peptides. This review summarizes the physiological functions, the pathogenic implications, and the recent use of these molecules as biomarkers in several pathological conditions. A thorough literature review of the electronic healthcare databases MEDLINE, from January 1985 to September 2013, was conducted to identify articles and studies concerned with CgA and its processing. The search strategies utilized keywords such as chromogranin A, vasostatins 1 and 2, chromofungin, chromacin, pancreastatin, catestatin, WE14, chromostatin, GE25, parastatin, and serpinin and was supplemented by the screening of references from included papers and review articles. A total of 209 English-language, peer-reviewed original articles or reviews were examined. The analysis of the retrospective literature suggested that CgA and its several bioactive fragments exert a broad spectrum of regulatory activities by influencing the endocrine, the cardiovascular, and the immune systems and by affecting the glucose or calcium homeostasis. As some peptides exert similar effects, but others elicit opposite responses, the regulation of the CgA processing is critical to maintain homeostasis, whereas an unbalanced production of peptides that exert opposing effects can have a pathogenic role in several diseases. These clinical implications entail that CgA and its derived peptides are now used as diagnostic and prognostic markers or to monitor the response to pharmacological intervention not only in endocrine tumors, but also in cardiovascular, inflammatory, and neuropsychiatric diseases.

All mice harboring the X-linked Gata1 low mutation in a predominantly CD1 background are born anemic and thrombocytopenic. They recover from anemia at 1 month of age but remain thrombocytopenic all their life and develop myelofibrosis, a syndrome similar to human idiopathic myelofibrosis, at 12 months. The effects of the genetic background on the myelofibrosis developed by Gata1 low mice was assessed by introducing the mutation, by standard genetic approaches, in the C57BL/6 and DBA/2 backgrounds and by analyzing the phenotype of the different mutants at 12 to 13 (by histology) and 16 to 20 (by cytofluorimetry) months of age. Although all the Gata1 low mice developed fibrosis at 12 to 13 months, variegations were observed in the severity of the phenotype expressed by mutants of different backgrounds. In C57BL/6 mice, the mutation was no longer inherited in a Mendelian fashion, and fibrosis was associated with massive osteosclerosis. Instead, DBA/2 mutants, although severely anemic, expressed limited fibrosis and osteosclerosis and did not present tear-drop poikilocytes in blood or extramedullary hemopoiesis in liver up to 20 months of age. We propose that the variegation in myelofibrosis expressed by

Recent evidence suggests that mutations in the IntroductionAmong the GATA family of transcription factors, 1 Gata1 exerts a specific role in the control of erythroid, 2 megakaryocytic, 3,4 eosinophil, 5 and mast 6 cell differentiation. Genetic alterations of this gene, however, are not only associated with X-linked inherited erythroid or megakaryocytic disorders, but are also found in acquired myeloproliferative disorders. Each mutation is associated with a specific abnormality: point mutations that abrogate the ability of the amino-terminal zinc finger domain of the protein to bind either DNA or Fog1, a partner of Gata1, are found in inherited disorders. [7][8][9][10] On the other hand, frame shift and splice mutations encoding GATA1s, a protein lacking the amino-terminal domain, are associated not only with impaired inherited erythropoiesis, 11,12 but are also found in patients with megakaryocytic leukemia in Down syndrome, 13,14 in newborns with transient myeloproliferative syndromes, 15 and in one adult patient with megakaryocytic leukemia. 16 These observations suggest that, in addition to its effect on terminal differentiation, Gata1 might control the biologic properties of hematopoietic progenitor cells, predisposing them to accumulate secondary mutations in a multistep leukemogenic process. However, direct proof for a possible function of Gata1 in progenitor cells has not been provided as yet.We had previously described that hematopoietic tissues from mice carrying the hypomorphic Gata1 low mutation contain high numbers (ϳ10%) of "unique" progenitor cells that generate colonies composed of erythroblasts, megakaryocytes, and mast cells. 6 Predicted by the stochastic model of hematopoietic commitment, 17 such a trilineage progenitor has not been isolated prospectively as yet from the marrow of normal mice. In fact, antigenic profiling has prospectively divided normal murine progenitors into myeloid-and mast cell-restricted. The myeloid-restricted ones are further divided into granulomonocytic progenitors (GMPs), megakaryocytic-erythroid progenitors (MEPs), and common myeloid progenitors (CMPs). 18 GMPs correspond to cells previously defined, by functional clonogenesis, as colony-forming cells that generate in 7 days granulocytic, monomacrophagic and granulomonocytic colonies (CFU-Gs, CFU-Ms, and CFU-GMs). MEPs, on the other hand, include cells once functionally defined as those that generate megakaryocytic or erythroid colonies either in 3 days (CFU-MKs day3 and CFU-Es) or 7 days (CFU-MKs day7 and BFUEs). CMPs were functionally defined as multilineage progenitor cells, that is, those that generate colonies of multiple lineages after 12 to 15 days either in vitro (CFU-mix) or in vivo (spleen colony-forming cells, CFU-Ss day12 ). Mast cells are localized in extramedullary sites where they engage themselves in the process of allergic response and in the immune reaction against parasites. 19,20 As all the other hematopoietic cells, they derive from progenitor cells present in the marrow (and in the spleen) of ...

The term diabetic cardiomyopathy (DCM) labels an abnormal cardiac structure and performance due to intrinsic heart muscle malfunction, independently of other vascular co-morbidity. DCM, accounting for 50%–80% of deaths in diabetic patients, represents a worldwide problem for human health and related economics. Optimal glycemic control is not sufficient to prevent DCM, which derives from heart remodeling and geometrical changes, with both consequences of critical events initially occurring at the cardiomyocyte level. Cardiac cells, under hyperglycemia, very early undergo metabolic abnormalities and contribute to T helper (Th)-driven inflammatory perturbation, behaving as immunoactive units capable of releasing critical biomediators, such as cytokines and chemokines. This paper aims to focus onto the role of cardiomyocytes, no longer considered as “passive” targets but as “active” units participating in the inflammatory dialogue between local and systemic counterparts underlying DCM development and maintenance. Some of the main biomolecular/metabolic/inflammatory processes triggered within cardiac cells by high glucose are overviewed; particular attention is addressed to early inflammatory cytokines and chemokines, representing potential therapeutic targets for a prompt early intervention when no signs or symptoms of DCM are manifesting yet. DCM clinical management still represents a challenge and further translational investigations, including studies at female/male cell level, are warranted.

Human-induced pluripotent stem cells (hiPSCs) are reprogrammed cells that have hallmarks similar to embryonic stem cells including the capacity of self-renewal and differentiation into cardiac myocytes. The improvements in reprogramming and differentiating methods achieved in the past 10 years widened the use of hiPSCs, especially in cardiac research. hiPSC-derived cardiac myocytes (CMs) recapitulate phenotypic differences caused by genetic variations, making them attractive human disease models and useful tools for drug discovery and toxicology testing. In addition, hiPSCs can be used as sources of cells for cardiac regeneration in animal models. Here, we review the advances in the genetic and epigenetic control of cardiomyogenesis that underlies the significant improvement of the induced reprogramming of somatic cells to CMs; the methods used to improve scalability of throughput assays for functional screening and drug testing in vitro; the phenotypic characteristics of hiPSCs-derived CMs and their ability to rescue injured CMs through paracrine effects; we also cover the novel approaches in tissue engineering for hiPSC-derived cardiac tissue generation, and finally, their immunological features and the potential use in biomedical applications.

Rigorously defined reconstitution assays developed in recent years have allowed recognition of the delicate relationship that exists between hematopoietic stem cells and their niches. This balance ensures that hematopoiesis occurs in the marrow under steady-state conditions. However, during development, recovery from hematopoietic stress and in myeloproliferative disorders, hematopoiesis occurs in extramedullary sites whose microenvironments are still poorly defined. The hypomorphic Gata1low mutation deletes the regulatory sequences of the gene necessary for its expression in hematopoietic cells generated in the marrow. By analyzing the mechanism that rescues hematopoiesis in mice carrying this mutation, we provide evidence that extramedullary microenvironments sustain maturation of stem cells that would be otherwise incapable of maturing in the marrow.

Glucocorticoid receptor (GR) agonists increase erythropoiesis in vivo and in vitro.To clarify the effect of the dominant negative GR␤ isoform (unable to bind STAT-5) on erythropoiesis, erythroblast (EB) expansion cultures of mononuclear cells from 18 healthy (nondiseased) donors (NDs) and 16 patients with polycythemia vera (PV) were studied. GR␤ was expressed in all PV EBs but only in EBs from 1 ND. The A3669G polymorphism, which stabilizes GR␤ mRNA, had greater frequency in PV (55%; n ‫؍‬ 22; P ‫؍‬ .0028) and myelofibrosis (35%; n ‫؍‬ 20) patients than in NDs (9%; n ‫؍‬ 22) or patients with essential thrombocythemia (6%; n ‫؍‬ 15). Dexamethasone stimulation of ND cultures increased the number of immature EBs characterized by low GATA1 and ␤-globin expression, but PV cultures generated great numbers of immature EBs with low levels of GATA1 and ␤-globin irrespective of dexamethasone stimulation. In ND EBs, STAT-5 was not phosphorylated after dexamethasone and erythropoietin treatment and did not form transcriptionally active complexes with GR␣, whereas in PV EBs, STAT-5 was constitutively phosphorylated, but the formation of GR/STAT-5 complexes was prevented by expression of GR␤. These data indicate that GR␤ expression and the presence of A3669G likely contribute to development of erythrocytosis in PV and provide a potential target for identification of novel therapeutic agents. (Blood. 2011;118(2):425-436) IntroductionPolycythemia vera (PV) is a Philadelphia chromosome-negative myeloproliferative neoplasm (MPN) characterized by increased production of erythroid cells. 1 As in other MPNs, PV is associated with a gain-of-function mutation (JAK2V617F) of the JAK2 gene. [2][3][4] JAK2 is the first transduction element of many hematopoietic growth factor receptors, including the receptor for erythropoietin, the primary growth factor that controls erythroid cell production. 5 The observation that inhibition of JAK2V617F abrogates erythropoietin-independent growth of erythroid progenitors suggested the hypothesis that in PV, increased erythroid production is caused by constitutive activation of erythropoietin receptor signaling (STAT-5 and/or PI3K/Akt). [6][7][8] Because low and high levels of STAT-5 activation favor maturation and proliferation, respectively, in normal hematopoietic cells, 9,10 the presence of the JAK2V617F mutation in PV may increase the intrinsic proliferative potential of erythroid cells by increasing This concept is indirectly supported by the observation that hematopoietic progenitor cells from PV patients generate greater numbers of erythroblasts (EBs) in liquid culture than cells from healthy (nondiseased) donors (NDs). 7,12 In addition to erythropoietin, erythroid proliferation is also controlled by nuclear receptors such as the glucocorticoid receptor (GR). Evidence for this regulatory role is provided by clinical observations and in vitro studies of cultured EBs. Patients may develop erythrocytosis as the first manifestation of Cushing syndrome. 13 In addition, 50% of patients with Diamond-...