Atorvastatin and Conditioned Media from Atorvastatin-Treated Human Hematopoietic Stem/Progenitor-Derived Cells Show Proangiogenic Activity In Vitro but Not In Vivo.

Myeloid angiogenic cells (MAC) derive from hematopoietic stem/progenitor cells (HSPCs) that are mobilized from the bone marrow. They home to sites of neovascularization and contribute to angiogenesis by production of paracrine factors. The number and function of proangiogenic cells are impaired in patients with diabetes or cardiovascular diseases. Both conditions can be accompanied by decreased levels of heme oxygenase-1 (HMOX1), cytoprotective, heme-degrading enzyme. Our study is aimed at investigating whether precursors of myeloid angiogenic cells (PACs) treated with known pharmaceuticals would produce media with better proangiogenic activity in vitro and if such media can be used to stimulate blood vessel growth in vivo. We used G-CSF-mobilized CD34+ HSPCs, FACS-sorted from healthy donor peripheral blood mononuclear cells (PBMCs). Sorted cells were predominantly CD133+. CD34+ cells after six days in culture were stimulated with atorvastatin (AT), acetylsalicylic acid (ASA), sulforaphane (SR), resveratrol (RV), or metformin (Met) for 48 h. Conditioned media from such cells were then used to stimulate human aortic endothelial cells (HAoECs) to enhance tube-like structure formation in a Matrigel assay. The only stimulant that enhanced PAC paracrine angiogenic activity was atorvastatin, which also had ability to stabilize endothelial tubes in vitro. On the other hand, the only one that induced heme oxygenase-1 expression was sulforaphane, a known activator of a HMOX1 inducer-NRF2. None of the stimulants changed significantly the levels of 30 cytokines and growth factors tested with the multiplex test. Then, we used atorvastatin-stimulated cells or conditioned media from them in the Matrigel plug in vivo angiogenic assay. Neither AT alone in control media nor conditioned media nor AT-stimulated cells affected numbers of endothelial cells in the plug or plug's vascularization. Concluding, high concentrations of atorvastatin stabilize tubes and enhance the paracrine angiogenic activity of human PAC cells in vitro. However, the effect was not observed in vivo. Therefore, the use of conditioned media from atorvastatin-treated PAC is not a promising therapeutic strategy to enhance angiogenesis.

Murine Bone Marrow Mesenchymal Stromal Cells Respond Efficiently to Oxidative Stress Despite the Low Level of Heme Oxygenases 1 and 2.

AIMS: Mesenchymal stromal cells (MSCs) are heterogeneous cells from adult tissues that are able to differentiate in vitro into adipocytes, osteoblasts, or chondrocytes. Such cells are widely studied in regenerative medicine. However, the success of cellular therapy depends on the cell survival. Heme oxygenase-1 (HO-1, encoded by the Hmox1 gene), an enzyme converting heme to biliverdin, carbon monoxide, and Fe2+, is cytoprotective and can affect stem cell performance. Therefore, our study aimed at assessing whether Hmox1 is critical for survival and functions of murine bone marrow MSCs. RESULTS: Both MSC Hmox1+/+ and Hmox1-/- showed similar phenotype, differentiation capacities, and production of cytokines or growth factors. Hmox1+/+ and Hmox1-/- cells showed similar survival in response to 50 µmol/L hemin even in increased glucose concentration, conditions that were unfavorable for Hmox1-/- bone marrow-derived proangiogenic cells (BDMC). Hmox1+/+ MSCs but not fibroblasts retained low ROS levels even after prolonged incubation with 50 µmol/L hemin, although both cell types have a comparable Hmox1 expression and similarly increase its levels in response to hemin. MSCs Hmox1-/- treated with hemin efficiently induced expression of a vast panel of antioxidant genes, especially enzymes of the glutathione pathway. Innovation and Conclusion: Hmox1 overexpression is a popular strategy to enhance viability and performance of MSCs after the transplantation. However, murine MSCs Hmox1-/- do not differ from wild-type MSCs in phenotype and functions. MSC Hmox1-/- show better resistance to hemin than fibroblasts and BDMCs and rapidly react to the stress by upregulation of quintessential genes in antioxidant response. Antioxid. Redox Signal. 00, 000-000.

Information processing in the NF-κB pathway.

The NF-κB pathway is known to transmit merely 1 bit of information about stimulus level. We combined experimentation with mathematical modeling to elucidate how information about TNF concentration is turned into a binary decision. Using Kolmogorov-Smirnov distance, we quantified the cell's ability to discern 8 TNF concentrations at each step of the NF-κB pathway, to find that input discernibility decreases as signal propagates along the pathway. Discernibility of low TNF concentrations is restricted by noise at the TNF receptor level, whereas discernibility of high TNF concentrations it is restricted by saturation/depletion of downstream signaling components. Consequently, signal discernibility is highest between 0.03 and 1 ng/ml TNF. Simultaneous exposure to TNF or LPS and a translation inhibitor, cycloheximide, leads to prolonged NF-κB activation and a marked increase of transcript levels of NF-κB inhibitors, IκBα and A20. The impact of cycloheximide becomes apparent after the first peak of nuclear NF-κB translocation, meaning that the NF-κB network not only relays 1 bit of information to coordinate the all-or-nothing expression of early genes, but also over a longer time course integrates information about other stimuli. The NF-κB system should be thus perceived as a feedback-controlled decision-making module rather than a simple information transmission channel.

Interferon lambda polymorphisms associate with body iron indices and hepatic expression of interferon-responsive long non-coding RNA in chronic hepatitis C.

Single nucleotide polymorphisms (SNPs) within DNA region containing interferon lambda 3 (IFNL3) and IFNL4 genes are prognostic factors of treatment response in chronic hepatitis C (CHC). Iron overload, frequently diagnosed in CHC, is associated with unfavorable disease course and a risk of carcinogenesis. Its etiology and relationship with the immune response in CHC are not fully explained. Our aim was to determine whether IFNL polymorphisms in CHC patients associate with body iron indices, and whether they are linked with hepatic expression of genes involved in iron homeostasis and IFN signaling. For 192 CHC patients, four SNPs within IFNL3-IFNL4 region (rs12979860, rs368234815, rs8099917, rs12980275) were genotyped. In 185 liver biopsies, histopathological analyses were performed. Expression of five mRNAs and three long non-coding RNAs (lncRNAs) was determined with qRT-PCR in 105 liver samples. Rs12979860 TT or rs8099917 GG genotypes as well as markers of serum and hepatocyte iron overload associated with higher activity of gamma-glutamyl transpeptidase and liver steatosis. The presence of two minor alleles in any of the tested SNPs predisposed to abnormally high serum iron concentration and correlated with higher hepatic expression of lncRNA NRIR. On the other hand, homozygosity in any major allele associated with higher viral load. Patients bearing rs12979860 CC genotype had lower hepatic expression of hepcidin (HAMP; P = 0.03). HAMP mRNA level positively correlated with serum iron indices and degree of hepatocyte iron deposits. IFNL polymorphisms influence regulatory pathways of cellular response to IFN and affect body iron balance in chronic hepatitis C virus infection.

Importins promote high-frequency NF-κB oscillations increasing information channel capacity.

BACKGROUND: Importins and exportins influence gene expression by enabling nucleocytoplasmic shuttling of transcription factors. A key transcription factor of innate immunity, NF-κB, is sequestered in the cytoplasm by its inhibitor, IκBα, which masks nuclear localization sequence of NF-κB. In response to TNFα or LPS, IκBα is degraded, which allows importins to bind NF-κB and shepherd it across nuclear pores. NF-κB nuclear activity is terminated when newly synthesized IκBα enters the nucleus, binds NF-κB and exportin which directs the complex to the cytoplasm. Although importins/exportins are known to regulate spatiotemporal kinetics of NF-κB and other transcription factors governing innate immunity, the mechanistic details of these interactions have not been elucidated and mathematically modelled. RESULTS: Based on our quantitative experimental data, we pursue NF-κB system modelling by explicitly including NF-κB-importin and IκBα-exportin binding to show that the competition between importins and IκBα enables NF-κB nuclear translocation despite high levels of IκBα. These interactions reduce the effective relaxation time and allow the NF-κB regulatory pathway to respond to recurrent TNFα pulses of 45-min period, which is about twice shorter than the characteristic period of NF-κB oscillations. By stochastic simulations of model dynamics we demonstrate that randomly appearing, short TNFα pulses can be converted to essentially digital pulses of NF-κB activity, provided that intervals between input pulses are not shorter than 1 h. CONCLUSIONS: By including interactions involving importin-α and exportin we bring the modelling of spatiotemporal kinetics of transcription factors to a more mechanistic level. Basing on the analysis of the pursued model we estimated the information transmission rate of the NF-κB pathway as 1 bit per hour. REVIEWERS: This article was reviewed by Marek Kimmel, James Faeder and William Hlavacek.

[Still's disease or systemic lupus erythematosus in a young adult patient--diagnostic doubts]. / Choroba Stilla czy toczen rumieniowaty ukladowy u mlodego doroslego pacjenta--watpliwosci diagnostyczne.

Systemic lupus erythematosus and Still's disease are chronic autoimmune disorders of unknown etiology. Symptomatology of these diseases may be similar causing diagnostic difficulties. Long-term observation and immunological studies are essential to identify the definite disorder. We present a case of a 24-year-old patient with high fever, sore throat and arthritis. During hospitalization rash accompanying fever, nodular erythema, pulmonary changes, liver damage and splenomegaly were observed. Although initially adult-onset Still's disease was diagnosed according to the Yamaguchi criteria, the diagnosis of systemic lupus erythematosus was made after re-analysis of the clinical course and immunological tests.