The C allele of JAK2 rs4495487 is an additional candidate locus that contributes to myeloproliferative neoplasm predisposition in the Japanese population

<p>Abstract</p> <p>Background</p> <p>Polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) are myeloproliferative neoplasms (MPNs) characterized in most cases by a unique somatic mutation, <it>JAK2 </it>V617F. Recent studies revealed that <it>JAK2 </it>V617F occurs more frequently in a specific <it>JAK2 </it>haplotype, named <it>JAK2 </it>46/1 or GGCC haplotype, which is tagged by rs10974944 (C/G) and/or rs12343867 (T/C). This study examined the impact of single nucleotide polymorphisms (SNPs) of the <it>JAK2 </it>locus on MPNs in a Japanese population.</p> <p>Methods</p> <p>We sequenced 24 <it>JAK2 </it>SNPs in Japanese patients with PV. We then genotyped 138 MPN patients (33 PV, 96 ET, and 9 PMF) with known <it>JAK2 </it>mutational status and 107 controls for a novel SNP, in addition to two SNPs known to be part of the 46/1 haplotype (rs10974944 and rs12343867). Associations with risk of MPN were estimated by odds ratios and their 95% confidence intervals using logistic regression.</p> <p>Results</p> <p>A novel locus, rs4495487 (T/C), with a mutated T allele was significantly associated with PV. Similar to rs10974944 and rs12343867, rs4495487 in the <it>JAK2 </it>locus is significantly associated with <it>JAK2</it>-positive MPN. Based on the results of SNP analysis of the three <it>JAK2 </it>locus, we defined the "GCC genotype" as having at least one minor allele in each SNP (G allele in rs10974944, C allele in rs4495487, and C allele in rs12343867). The GCC genotype was associated with increased risk of both <it>JAK2 </it>V617F-positive and <it>JAK2 </it>V617F-negative MPN. In ET patients, leukocyte count and hemoglobin were significantly associated with <it>JAK2 </it>V617F, rather than the GCC genotype. In contrast, none of the <it>JAK2 </it>V617F-negative ET patients without the GCC genotype had thrombosis, and splenomegaly was frequently seen in this subset of ET patients. PV patients without the GCC genotype were significantly associated with high platelet count.</p> <p>Conclusions</p> <p>Our results indicate that the C allele of <it>JAK2 </it>rs4495487, in addition to the 46/1 haplotype, contributes significantly to the occurrence of <it>JAK2 </it>V617F-positive and <it>JAK2 </it>V617F-negative MPNs in the Japanese population. Because lack of the GCC genotype represents a distinct clinical-hematological subset of MPN, analyzing <it>JAK2 </it>SNPs and quantifying <it>JAK2 </it>V617F mutations will provide further insights into the molecular pathogenesis of MPN.</p

Insulin-Like Growth Factors Promote Vasculogenesis in Embryonic Stem Cells

The ability of embryonic stem cells to differentiate into endothelium and form functional blood vessels has been well established and can potentially be harnessed for therapeutic angiogenesis. However, after almost two decades of investigation in this field, limited knowledge exists for directing endothelial differentiation. A better understanding of the cellular mechanisms regulating vasculogenesis is required for the development of embryonic stem cell-based models and therapies. In this study, we elucidated the mechanistic role of insulin-like growth factors (IGF1 and 2) and IGF receptors (IGFR1 and 2) in endothelial differentiation using an embryonic stem cell embryoid body model. Both IGF1 or IGF2 predisposed embryonic stem to differentiate towards a mesodermal lineage, the endothelial precursor germ layer, as well as increased the generation of significantly more endothelial cells at later stages. Inhibition of IGFR1 signaling using neutralizing antibody or a pharmacological inhibitor, picropodophyllin, significantly reduced IGF-induced mesoderm and endothelial precursor cell formation. We confirmed that IGF-IGFR1 signaling stabilizes HIF1α and leads to up-regulation of VEGF during vasculogenesis in embryoid bodies. Understanding the mechanisms that are critical for vasculogenesis in various models will bring us one step closer to enabling cell based therapies for neovascularization

Prox1 Regulates the Notch1-Mediated Inhibition of Neurogenesis

During development of the spinal cord, Prox1 controls the balance between proliferation and differentiation of neural progenitor cells via suppression of Notch1 gene expression

In Vivo Phenotyping of Familial Parkinson’s Disease with Human Induced Pluripotent Stem Cells: A Proof-of-Concept Study

Parkinson’s disease (PD) is the second most common neurodegenerative disorder. We have previously developed a disease-in-a-dish model for familial PD using induced pluripotent stem cells (iPSCs) from two patients carrying the p.A53T α-synuclein (αSyn) mutation. By directed differentiation, we generated a model that displays disease-relevant phenotypes, including protein aggregation, compromised neurite outgrowth, axonal neuropathology and synaptic defects. Here we investigated the in vivo phenotypes of iPSCs, derived from one patient, after transplantation in a lesion mouse model established by unilateral intrastriatal 6-hydroxydopamine injection in the immunosuppressed NOD/SCID strain. Immunohistochemistry revealed that despite the disease-related characteristics that mutant cells displayed when maintained up to 70 days in vitro, they could survive and differentiate in vivo over a 12-week period. However, some differences were noted between patient-derived and control grafts, including a significant rise in αSyn immunoreactivity that might signal a first step towards pathology. Moreover, control-derived grafts appeared to integrate better than PD grafts within the host tissue extending projections that formed more contacts with host striatal neurons. Our data suggest that the distinct disease-related characteristics which p.A53T cells develop in vitro, may be attenuated or take longer to emerge in vivo after transplantation within the mouse brain. Further analysis of the phenotypes that patient cells acquire over longer periods of time as well as the use of multiple iPSC clones from different patients should extend our current proof-of-concept study and provide additional evidence for in vivo disease modeling. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

Short-term effect of orlistat on dietary glycotoxins in healthy women and women with polycystic ovary syndrome

Exogenous advanced glycation endproducts (AGEs, known atherogenic molecules) abundant in everyday precooked, rich in fat, overheated meals can possibly contribute to the increased risk for diabetes and cardiovascular disease in women with polycystic ovary syndrome (PCOS). The aim of the present study was to investigate the effect of a lipase inhibitor on absorbed food glycotoxins in healthy women and those with PCOS. A 2-day protocol was followed. In the first day, a meal rich in AGE was provided, which on the second day was followed by two 120-mg capsules of lipase inhibitor, orlistat. Serum AGE levels were evaluated at baseline (0 hours), and at 3 and 5 hours postmeal during the study. Thirty-six women were Studied, 15 controls (mean age, 28.80 +/- 5.47 years; body mass index, 25.85 +/- 6.73 kg/m(2)) and 21 with PCOS (mean age, 25.29 +/- 5.06 years; body mass index, 30.40 +/- 7.51 kg/m(2)) (University Hospital, Athens, Greece, institutional practice). Serum AGE levels, on day 1, were significantly increased both in the control group and in the PCOS group as compared with basal values (control group, 14.1%; PCOS group, 6.0%; P &lt;.001). The corresponding rise was significantly lower on day 2 when the same meal was combined with orlistat (control group, 4.1%; PCOS group, 2.0%; P &lt;.01). A limitation of the study is that it is a nonplacebo, nonrandomized therapeutic trial where each Subject is considered as its own control. In conclusion, this study demonstrated the beneficial effect of orlistat on the absorption of food glycotoxins. (c) 2006 Elsevier Inc. All rights reserved

Amifostine protects mouse liver against radiation-induced autophagy blockage

Background/Aim: Amifostine is the only selective normal tissue cytoprotector, approved for the protection against platinum toxicities and radiotherapy-induced xerostomia. Free radical scavenger and DNA repair activities have been attributed to the drug. Materials and Methods: We investigated the effect of amifostine on autophagy, lysosomal biogenesis and lipophagy of normal mouse liver exposed to clinically relevant doses of radiation. Results: The study provides evidence that ionizing radiation blocks autophagy activity and lysosomal biogenesis in normal mouse liver. Amifostine, protects the liver autophagic machinery and induces lysosomal biogenesis. By suppressing autophagy, ionizing radiation induces lipid droplet accumulation, while pre-treatment with amifostine protects lipophagy and up-regulates the TIP47 protein and mRNA levels, showing a maintenance of lipid metabolism in the liver cells. Conclusion: It is concluded that amifostine, aside to DNA protection activity, exerts its cytoprotective function by preventing radiation-induced blockage of autophagy, lysosomal biogenesis and lipophagy

High content screening and proteomic analysis identify a kinase inhibitor that rescues pathological phenotypes in a patient-derived model of Parkinson’s disease

Combining high throughput screening approaches with induced pluripotent stem cell (iPSC)-based disease modeling represents a promising unbiased strategy to identify therapies for neurodegenerative disorders. Here we applied high content imaging on iPSC-derived neurons from patients with familial Parkinson’s disease bearing the G209A (p.A53T) α-synuclein (αSyn) mutation and launched a screening campaign on a small kinase inhibitor library. We thus identified the multi-kinase inhibitor BX795 that at a single dose effectively restores disease-associated neurodegenerative phenotypes. Proteomics profiling mapped the molecular pathways underlying the protective effects of BX795, comprising a cohort of 118 protein-mediators of the core biological processes of RNA metabolism, protein synthesis, modification and clearance, and stress response, all linked to the mTORC1 signaling hub. In agreement, expression of human p.A53T-αSyn in neuronal cells affected key components of the mTORC1 pathway resulting in aberrant protein synthesis that was restored in the presence of BX795 with concurrent facilitation of autophagy. Taken together, we have identified a promising small molecule with neuroprotective actions as candidate therapeutic for PD and other protein conformational disorders. © 2022, The Author(s)