Pathophysiological correlation of arginase-1 in development of type 2 diabetes from obesity in adolescents.

BACKGROUND: There is great interest to understand causal pathophysiological correlation between obesity and diabetes mellitus (DM). Vascular endothelial dysfunction is crucially involved in pathogenesis of vascular complications in DM. Recently, increased arginase expression and activity have been described as underlying mechanisms of endothelial dysfunction in DM and vascular inflammation in obesity. By limiting L-arginine bioavailability to endothelial nitric oxide synthase (NOS III), nitric oxide production is potentially impaired. METHODS: We investigated the impact of plasma from diabetic and obese adolescents on arginase and NOS III expression in cultured human endothelial cells (ECs). A total of 148 male adolescents participated in this study including 18 obese, 28 type 1-, 28 type 2-DM patients, and 74 age-matched healthy volunteers. RESULTS: A concurrent increase in arginase-1 (1.97-fold) and decrease in NOS III expression (1.45-fold) was observed in ECs exposed to type 2 diabetic plasma compared to control subjects. ECs incubated with type 1 DM plasma had a diminished NOS III level without impact on arginase-1 expression. Urea-assay featured an increased arginase activity in treated ECs with type 1- or 2-DM plasma. Despite increased pro-inflammatory cytokines and chemokines in obese plasma, arginase-1 expression/activity did not change in treated ECs. However, NOS III expression was significantly reduced. Pearson analysis revealed positive correlation between arginase-1, but not NOS III, expression with FBS in ECs treated with type 2-DM plasma. CONCLUSIONS: Our data demonstrate that increased arginase-1 expression/activity in ECs, as critical pathogenic factor is correlated with development of obesity-related type 2-DM and linked vascular disease.

Regulation of MAP kinase-mediated endothelial dysfunction in hyperglycemia via arginase I and eNOS dysregulation.

Emerging evidence suggests that arginase contributes to endothelial dysfunction in diabetes. Intracellular signaling pathways, which interplay between arginase and eNOS enzyme activity leading to the development of endothelial dysfunction in hyperglycemia are not fully understood. Here, we analyzed the possible involvement of hyperglycemia (HG) induced arginase expression in eNOS protein regulation and activity and also the impact of arginase inhibition on eNOS activity. Furthermore, the roles of p38 MAPK and Erk1/2 phosphorylation in upregulation of arginase expression and eNOS dysregulation in endothelial cells (ECs) under hyperglycemia were evaluated. Protein analysis showed a concurrent increase in arginase I expression and decrease in eNOS expression and phosphorylation at Ser1177 under HG conditions. There was no simultaneous change in phosphorylation of eNOS at Thr495 in HG. Arginase inhibition prevented increased arginase activity, restored impaired NO bioavailability and reduced superoxide anion generation. Inhibition of MAP-kinases demonstrated that, unlike Erk1/2, p38 MAPK is an upstream activator in a signaling cascade leading to increased arginase I in HG conditions. P38 MAPK protein expression and phosphorylation were increased in response to HG. In the presence of a p38 MAPK inhibitor, HG-induced arginase expression was blunted. Although Erk1/2 was activated in HG, increased arginase expression was not blocked by co-treatment with an Erk1/2 inhibitor. Activation of both, p38 MAPK and Erk1/2 in HG, induced a downregulation in eNOS activity. Hence, applying MAPK inhibitors increased eNOS phosphorylation in HG. In conclusion, these findings demonstrate contributions of arginase I in the development of endothelial cell dysfunction under HG conditions via impaired eNOS regulation, which maybe mediated by p38 MAPK.

Erratum: Mitochondrial G8292A and C8794T mutations in patients with Niemann-Pick disease type C.

[This corrects the article DOI: 10.3892/br.2018.1095.].

WISP3 mutation associated with pseudorheumatoid dysplasia.

Progressive pseudorheumatoid dysplasia (PPD) is a skeletal dysplasia characterized by predominant involvement of articular cartilage with progressive joint stiffness. Here we report genetic characterization of a consanguineous family segregating an uncharacterized from of skeletal dysplasia. Whole-exome sequencing of four affected siblings and their parents identified a loss-of-function homozygous mutation in the WISP3 gene, leading to diagnosis of PPD in the affected individuals. The identified variant (Chr6: 112382301; WISP3:c.156C>A p.Cys52*) is rare and predicted to cause premature termination of the WISP3 protein.

Cardiomyogenesis of embryonic stem cells upon purinergic receptor activation by ADP and ATP.

Purinergic signaling may be involved in embryonic development of the heart. In the present study, the effects of purinergic receptor stimulation on cardiomyogenesis of mouse embryonic stem (ES) cells were investigated. ADP or ATP increased the number of cardiac clusters and cardiac cells, as well as beating frequency. Cardiac-specific genes showed enhanced expression of α-MHC, MLC2v, α-actinin, connexin 45 (Cx45), and HCN4, on both gene and protein levels upon ADP/ATP treatment, indicating increased cardiomyogenesis and pacemaker cell differentiation. Real-time RT-PCR analysis of purinergic receptor expression demonstrated presence of P2X1, P2X4, P2X6, P2X7, P2Y1, P2Y2, P2Y4, and P2Y6 on differentiating ES cells. ATP and ADP as well as the P2X agonists ß,γ-methylenadenosine 5'-triphosphate (ß,γ-MetATP) and 8-bromoadenosine 5'-triphosphate (8-Br-ATP) but not UTP or UDP transiently increased the intracellular calcium concentration ([Ca(2+)](i)) as evaluated by the calcium indicator Fluo-4, whereas no changes in membrane potential were observed. [Ca(2+)](i) transients induced by ADP/ATP were abolished by the phospholipase C-ß (PLC-ß) inhibitor U-73122, suggesting involvement of metabotropic P2Y receptors. Furthermore, partial inhibition of [Ca(2+)](i) transients was achieved in presence of MRS2179, a selective P2Y1 receptor antagonist, whereas PPADS, a non-selective P2 receptor inhibitor, completely abolished the [Ca(2+)](i) response. Consequently, cardiomyocyte differentiation was decreased upon long term co-incubation of cells with ADP and P2 receptor antagonists. In summary, activation of purinoceptors and the subsequent [Ca(2+)](i) transients enhance the differentiation of ES cells toward cardiomyocytes. Purinergic receptor stimulation may be a promising strategy to drive the fate of pluripotent ES cells into a particular population of cardiomyocytes.

Livin, a novel marker in lymphoma type distinction.

Despite advances in immunohistochemical and molecular diagnostics, there are persistent difficulties in differentiating between several subtypes of non-Hodgkin lymphoma (NHL) and classic Hodgkin lymphoma (CHL). Considering high level of livin expression in hematologic malignancies, we aimed to examine the utility of livin expression ratio, as an ancillary biomarker, in distinguishing CHL from NHL in ambiguous cases. We evaluated livin expression in 38 CHL, 23 NHL, and 39 nonneoplastic lymph nodes in paraffin-embedded blocks. Tissue microarray-based semiquantitative immunoflourecent staining was applied for protein expression. Criterion standard of diagnosis was based on selection of only definite cases and not the cases suspected by hemathopathologists. A significant difference was found in the livin/GAPDH mean ratio (M.R) of expression between NHL and CHL cases. A receiver operating characteristic curve analysis confirmed 0.6370 to be the best diagnostic cut-off value for the livin/GAPDH expression M.R in diffuse large B-cell lymphoma (DLBCL) (area under the curve = 0.944); it yielded 92% sensitivity, 94% specificity, likelihood ratios positive 17.5, and likelihood ratios negative 0.07 for diagnosing DLBCL from CHL. Mean ratio of livin/Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) expression seems to be a valuable index in differentiating DLBCL from CHL. We suggested an optimal cut-off point for livin/GAPDH expression M.R with a high sensitivity and specificity. Thus, in diagnostically difficult cases of DLBCL and CHL, focus on livin as marker may provide useful corroborative information.

Apoptosis inhibition or inflammation: the role of NAIP protein expression in Hodgkin and non-Hodgkin lymphomas compared to non-neoplastic lymph node.

BACKGROUND: Inhibitors of Apoptosis (IAP) family play a critical role in apoptosis and inflammatory response. Neuronal Apoptosis Inhibitory Protein (NAIP), as a member of both IAPs and NLR families (NOD-Like Receptor), is a unique IAP harboring NOD (Nucleotide Oligomerization Domain) and LLR (Leucine Rich Repeat) motifs. Considering these motifs in NAIP, it has been suggested that the main function of NAIP is distinct from other members of IAPs. As a member of NLR, NAIP mediates the assembly of 'Inflammasome' for inflammatory caspase activation. Pathologic expression of NAIP has been reported not only in some infectious and inflammatory diseases but also in some malignancies. However, there is no report to elucidate NAIP expression in lymphomatic malignancies. METHODS: In this study, we examined NAIP protein expression in 101 Formalin-Fixed Paraffin-Embedded blocks including samples from 39 Hodgkin Lymphoma and 23 Non Hodgkin Lymphoma cases in comparison with 39 control samples (30 normal and 9 Reactive Lymphoid Hyperplasia (RLH) lymph nodes) using semi-quantitative immuno-flourecent Staining. RESULTS: NAIP expression was not statistically different in lymphoma samples neither in HL nor in NHL cases comparing to normal samples. However, we evaluated NAIP expression in normal and RLH lymph nodes. Surprisingly, we have found a statistically significant-difference between the NAIP expression in RLH (M.R of NAIP/GAPDH expression = 0.6365 ± 0.017) and normal lymph node samples (M.R of NAIP/GAPDH expression = 0.5882 ± 0.047) (P < 0.01). CONCLUSIONS: These findings show that the regulation of apoptosis could not be the main function of NAIP in the cell, so the pathologic expression of NAIP is not involved in lymphoma. But, we concluded that the over expression of NAIP has more effective role in the inflammatory response. Also, this study clarifies the NAIP expression level in lymphoma which is required for IAPs profiling in order to be used in potential translational applications of IAPs.