[Protein tyrosine phosphatase receptor type O (PTPRO) promotes phagocytic activity of alveolar epithelial cells via activating AKT signal pathway in LPS induced acute lung injury].

Objective To investigate the effect of protein tyrosine phosphatase receptor type O (PTPRO) on the phagocytic activity of alveolar epithelial cells in LPS-induced acute lung injury. Methods Mice were randomly divided into the normal control group and LPS stimulation group. The infiltration of inflammatory cells was detected by HE staining. The cytokine TNF-α level in lung was analyzed by ELISA. Western blotting was performed to detect the effect of LPS on PTPRO protein expression in lung. After the expression of PTPRO in MLE-12 cells was silenced by siRNA in vitro, flow cytometry was used to detect the effects of LPS and PTPRO siRNA on the phagocytic activity of MLE-12 cells, and the effects of LPS and PTPRO siRNA on the expression of PTPRO, AKT and phosphorylated AKT protein were measured by Western blotting. Results After the establishment of murine acute lung injury model by LPS injection(1 mg/kg), the infiltrated polymorphonuclear leukocytes were markedly increased. The level of TNF-α in lung tissue and the expression of PTPRO in MLE-12 cells were both significantly increased after LPS stimulation. However, the activity of MLE-12 cells to phagocytose fluorescent microbeads was evidently decreased after silencing PTPRO. Furthermore, silencing PTPRO induced a remarkable decrease in the phosphorylation of AKT in MLE-12 cells. Conclusion PTPRO can promote phagocytic activity of MLE-12 cells via activating AKT signaling pathway.

Independent oncogenic and therapeutic significance of phosphatase PRL-3 in FLT3-ITD-negative acute myeloid leukemia.

BACKGROUND: Internal tandem duplication of FMS-like tyrosine kinase (FLT3-ITD) is well known to be involved in acute myeloid leukemia (AML) progression, but FLT3-ITD-negative AML cases account for 70% to 80% of AML, and the mechanisms underlying their pathology remain unclear. This study identifies protein tyrosine phophatase PRL-3 as a key mediator of FLT3-ITD-negative AML. METHODS: A total of 112 FLT3-ITD-negative AML patients were sampled between 2010 and 2013, and the occurrence of PRL-3 hyperexpression in FLT3-ITD-negative AML was evaluated by multivariate probit regression analysis. Overexpression or depletion of endogenous PRL-3 expression with the specific small interfering RNAs was performed to investigate the role of PRL-3 in AML progression. Xenograft models were also used to confirm the oncogenic role of PRL-3. RESULTS: Compared to healthy donors, PRL-3 is upregulated more than 3-fold in 40.2% of FLT3-ITD-negative AML patients. PRL-3 expression level is adversely correlated to the overall survival of the AML patients, and the AML relapses accompany with re-upregulation of PRL-3. Mechanistically, aberrant PRL-3 expression promoted cell cycle progression and enhanced the antiapoptotic machinery of AML cells to drug cytotoxicity through downregulation of p21 and upregulation of Cyclin D1 and CDK2 and activation of STAT5 and AKT. Depletion of endogenous PRL-3 sensitizes AML cells to therapeutic drugs, concomitant with apoptosis by upregulation of cleaved PARP (poly ADP ribose polymerase) and apoptosis-related caspases. Xenograft assays further confirmed PRL-3's oncogenic role in leukemogenesis. CONCLUSIONS: Our results demonstrated that PRL-3 is a novel independent crucial player in both FLT3-ITD-positive and FLT3-ITD-negative AML and could be a potential therapeutic target.

Examination of novel non-phosphorus-containing phosphotyrosyl mimetics against protein-tyrosine phosphatase-1B and demonstration of differential affinities toward Grb2 SH2 domains.

Inhibitory potencies were compared of several mono- and dicarboxy-based pTyr mimetics in Grb2 SH2 domain versus PTP1B assays. Although in both systems pTyr residues provide critical binding elements, significant differences in the manner of recognition exist between the two. This is reflected in the current study, where marked variation in relative potencies was observed between the two systems. Of particular note was the poor potency of all monocarboxy-based pTyr mimetics against PTP1B when incorporated into a hexapeptide platform. The recently reported high PTP1B inhibitory potency of similar phenylphosphate mimicking moieties displayed in small molecule, non-peptide structures, raises questions on the limitations of using peptides as platforms for pTyr mimetics in the discovery of small molecule inhibitors.

[Effect of preparations of protein Yop encoded by Yersinia pestis calcium-dependence plasmid on mice]. / Deistvie na myshei preparatov belkov Yop, kodiruemykh plazmidoi kal'tsiizavisimosti Yersinia pestis.

The impact of the preparations of Y. pestis secreted proteins Yop (YopH-M, YopB, YopD-N, YopE) on mice immunized with 3 s.c. injections was studied. Though these proteins failed to protect the animals from plague, they stimulated the immunobiological transformation in the immunized animals. YopB and YopD-N were found to have the highest immunobiological activity with respect to mice. The preparation of YopB induced the production of the highest titers of specific antibodies and stimulated cell-mediated immune response. The injection of YopD-N to mice led to a considerable decrease in the proliferative capacity of splenocytes in vitro in response to stimulation with nonspecific mitogen ConA, as well as to pathological changes in the kidneys.