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Background RNA interference (RNAi) has emerged as a promising technology for insect pest control. Because of the accumulation of high levels of long double-stranded RNAs (dsRNAs) in plastids, it was previously shown that expression of dsRNAs from plastid genome led to higher mortality of some insect pests with chewing mouthparts than dsRNAs expression from nuclear genome. However, whether plastid-expressed dsRNAs have effects on phloem sap-sucking pests is unknown. In this study, we compared the RNAi effects of nuclear transgenic and transplastomic plants on the whitefly Bemisia tabaci, a serious sap-sucking pest. Results Nuclear transgenic and transplastomic tobacco plants were developed for the expression of dsRNA against BtACTB gene of Bemisia tabaci, respectively. Feeding nuclear transgenic plants to Bemisia tabaci resulted in reduced gene expression of BtACTB and survival rate, and impaired fecundity of Bemisia tabaci. We did not observe any effects of transplastomic plants on Bemisia tabaci fitness. Furthermore, we found that the inability of B. tabaci to obtain dsRNAs from plastids might restrict its RNAi responses. Conclusion Our study indicated that the expression of dsRNAs in nuclear transgenic plants was more effective than that in transplastomic plants for the control of Bemisia tabaci. The inaccessibility of Bemisia tabaci to plastids contributes to the inefficiency of plastid-mediated RNAi. Our findings are of great significance to future optimization of transgenically delivered RNAi approaches for efficient controlling of sap-sucking pests. © 2020 Society of Chemical Industry.

Although ~80% of newly diagnosed pediatric patients with acute lymphoblastic leukemia (ALL) become disease‑free following appropriate treatment, relapses frequently occur, with dismal prognosis. Therefore, it is urgent to develop novel therapeutic modalities. Resistance to chemotherapy is a major obstacle for the treatment of relapsed ALL. It has been indicated that Wnt pathway is potentially associated with leukemia recurrence. In the current study, a vincristine (VCR)‑resistant variant of the human ALL cell line BALL‑1 (BALL‑1/VCR) that also had relatively specific resistance to both doxorubicin and etoposide was generated. Over‑activation of the Wnt/β‑catenin signaling pathway was observed in BALL‑1/VCR cells, whereas Dickkopf‑related protein 1 selectively suppressed the Wnt signaling pathway and sensitized the response of BALL‑1/VCR to anticancer agents. In addition, prednisolone exposure in combination with Wnt inhibition restored chemo‑sensitivity in relapsed ALL blasts. Since the resistance of BALL‑1/VCR cells is potentially attributed to the overexpression of MDR‑associated protein 1 (MRP1), the development of drug resistance in relapsed ALL may associated with the overexpression of MRP1 and P‑glycoprotein. The results of this study demonstrated that, as a potential candidate to mimic relapsed ALL, BALL‑1/VCR could be used in further research, while Wnt‑inhibition may become a promising therapeutic approach for treating ALL.

Owing to their immunosuppressive properties mesenchymal stem cells (MSCs) are widely applicable in the treatment of autoimmune disease. The aim of this study was to investigate whether the indoleamine 2,3-dioxygenase-1 (IDO-1) and cyclooxygenase-2 (COX-2) genes enhanced the immunosuppressive functional ability of MSCs following stable transfection. To strengthen the immunomodulatory ability of MSCs, IDO-1 and COX-2 were overexpressed in umbilical cord progenitor cell-derived MSCs using recombinant plasmids and electroporation. RT-qPCR analysis and western blotting confirmed the expression of IDO-1 and COX-2 in transfected MSCs. Further functional assays in co-culture experiments, including lymphocyte proliferation and cyto-toxicity assays showed that COX-2-transfected MSCs possessed more potent immunomodulatory cells than the untreated MSCs, or MSCs transfected with IDO-1. Additionally, synthesis of interferon-γ and tumor necrosis factor-α (TNF-α) was significantly inhibited in lymphocytes co-cultured with COX-2-transfected MSCs, which was consistent with changes in immune-related genes in MSCs. An enhanced expression of IDO-1, COX-2, heme-oxygenase-1, inducible nitric-oxide synthase, TNF-α-stimulated gene/protein-6, transforming growth factor-β (TGF-β), human leukocyte antigen molecule 5 (HLA-G5) and interleukin-10 (IL-10) was identified following COX-2 transfection. We showed that the overexpression of COX-2 enhanced the immunosuppressive function of MSCs. COX-2-modified MSCs more potently inhibited the activation and proliferation of peripheral blood mononuclear cells.

Background: Cord blood transplantation (CBT) can be a life-saving procedure in the treatment of a broad variety of disorders, including hematologic, immune, and genetic diseases. However, delayed platelet recovery hinders the application of CBT. Purpose: The aim of this study was to determine the optimal combination of cytokines to amplify megakaryocyte (Mk). Methods: CB CD34+ cells were obtained by immunomagnetic isolation and amplified under four different cytokine combinations. CD34+ cells of the group with thrombopoietin (TPO), stem cell factor (SCF), Flt-3 ligand (FL), and interleukin-6 (IL-6) were collected on days 0, 3, 7, 10, and 14. Immunophenotype was analyzed by flow cytometry (FCM). Polyploidic Mk cultured cells were collected on days 7 and 14 for colony-forming unit-Mk assay. The NOD/SCID mice were injected with expanded CD34+ cells, and the peripheral blood (PB) and bone marrow (BM) were tested on 3, 7, and 14 days. Results: The group with TPO, SCF, FL, and IL-6 reached the maximal total expansion fold and Mk population at day 7, which was slightly reduced later. After transplantation into NOD/SCID mice with expanded CD34+ cells, the human CD41+ cells were detected in mice PB on day 3 and in BM on day 7, then disappeared after 14 days. The expressing of activated platelet CD 42b+/CD62P+ increased gradually after transplantation. Conclusion: Platelets can recover rapidly in vivo by means of expanded CD34+ cells with various cytokines. In our system, a group of TPO, SCF, FL, and IL-6 represents the best cytokine combination for expansion of Mk progenitor cells from CB CD34+ cells.

The AIOLOS gene is important in the control of mature B-lymphocyte differentiation and proliferation. Previous research has shown that deregulated AIOLOS expression is associated with adult B-cell acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia in human patients. However, the function of AIOLOS in childhood B-cell precursor (BCP)-ALL is not fully understood. In the present study, Nalm-6 cells were divided into three groups: the untransfected control (UT), the lentiviral vector control (Lenti-Mock) and the AIOLOS-overexpressing (Lenti-AIOLOS) group. Lenti-AIOLOS Nalm-6 cells were constructed by lentiviral transduction, followed by cell proliferation assay, cell-cycle analysis and apoptosis assay, to evaluate the effects of AIOLOS on proliferation, cell cycle distribution and apoptosis of Nalm-6 cells in vitro. Moreover, the expression levels of genes associated with apoptosis and the cell cycle, as well as the transcription factors IKZF1 and NF-κB, were investigated by quantitative reverse transcription-polymerase chain reaction and western blot analysis. The results showed that the proliferation of Nalm-6 cells in the Lenti-AIOLOS group was reduced by 16% on day 8 compared with cells in the UT group (P>0.05). The reduction peaked at 29% on day 10 (P