Immunotoxins constructed with chimeric,short-lived anti-CD22 monoclonal antibodies induce less vascular leak without loss of cytotoxicity

An immunotoxin (IT) constructed with RFB4, a murine anti-CD22 monoclonal antibody, and the “deglycosylated” A chain of ricin has shown activity at safe doses in patients with non-Hodgkin lymphoma and in children with acute lymphoblastic leukemia. The dose limiting toxicity is vascular leak syndrome (VLS), which appears to be due to a unique amino acid motif in the ricin toxin A (RTA) chain that damages vascular endothelial cells. We mutated recombinant (r) RTA to disable this site, but await testing of the IT prepared with this mutant RTA in humans. Another possible approach to reducing IT-induced VLS is to shorten the half-life of the IT in vivo. We previously constructed a mouse-human chimeric RFB4 by grafting the variable genes of RFB4 onto the human IgG1k constant regions. Here, we report the expansion of our panel of mutant chimeric RFB4s (mcRFB4s) that lack the ability to bind to the neonatal Fc receptor (FcRn). In comparison with cRFB4, which had a T1/2 of 263 h, the mcRFB4s had T1/2s ranging from 39 to 106 h. ITs were constructed with these mcRFB4s and rRTA. The mcRFB4-RTA ITs retained their cytotoxicity in vitro and had shorter half lives than the parental cRFB4-RTA IT. In addition, the mcRFB4 IT with the shortest T1/2 induced less pulmonary vascular leak in mice, which we have postulated is a surrogate marker for VLS in humans.     

The novel GrCEP12 peptide from the plant-parasitic nematode Globodera rostochiensis suppresses flg22-mediated PTI

The potato cyst nematode Globodera rostochiensis is a biotrophic pathogen that secretes effector proteins into host root cells to promote successful plant parasitism. In addition to the role in generating within root tissue the feeding cells essential for nematode development,¹ nematode secreted effectors are becoming recognized as suppressors of plant immunity.^2-4 Recently we reported that the effector ubiquitin carboxyl extension protein (GrUBCEP12) from G. rostochiensis is processed into free ubiquitin and a 12-amino acid GrCEP12 peptide in planta. Transgenic potato lines overexpressing the derived GrCEP12 peptide showed increased susceptibility to G. rostochiensis and to an unrelated bacterial pathogen Streptomyces scabies, suggesting that GrCEP12 has a role in suppressing host basal defense or possibly pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) during the parasitic interaction.³ To determine if GrCEP12 functions as a PTI suppressor we evaluated whether GrCEP12 suppresses flg22-induced PTI responses in Nicotiana benthamiana. Interestingly, we found that transient expression of GrCEP12 in N. benthamiana leaves suppressed reactive oxygen species (ROS) production and the induction of two PTI marker genes triggered by the bacterial PAMP flg22, providing direct evidence that GrCEP12 indeed has an activity in PTI suppression.     

Sevoflurane protects cardiomyocytes against hypoxia/reperfusion injury via LINC01133/miR-30a-5p axis

Previous studies failed to elucidate the detailed mechanisms of anesthetic preconditioning as a protective approach against ischemic/reperfusion (I/R) injury in cells. The present study mainly centered on discovering the mechanisms of Sevoflurane (Sev) in preventing cardiomyocytes against I/R injury. Human cardiomyocyte AC16 cell line was used to simulate I/R injury based on a hypoxia/reperfusion (H/R) model. After Sev treatment, cell viability and apoptosis were detected by MTT assay and flow cytometry, respectively. Lactate dehydrogenase (LDH) content was measured using an LDH Detection Kit. Relative mRNA and protein expressions of LINC01133, miR-30a-5p and apoptosis-related proteins were detected using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot as needed. Target gene of miR-30a-5p and their potential binding sites were predicted using Starbase and confirmed by dual-luciferase reporter assay. Cell behaviors were assessed again after miR-30a-5p and LINC01133 transfection. Sev could improve cell viability, reduce LDH leakage, and down-regulate the expressions of apoptosis-related proteins (Bax, cleaved caspase-3 and cleaved caspase-9) and LINC01133 as well as up-regulate miR-30a-5p and Bcl-2 expressions in H/R cells. MiR-30a-5p was the target of LINC01133, and up-regulating miR-30a-5p enhanced the effects of Sev in H/R cells, with a suppression on H/R-induced activation of the p53 signaling pathway. However, up-regulating LINC01133 reversed the enhancing effects of miR-30a-5p on Sev pretreatment in H/R cells. Sev could protect cardiomyocytes against H/R injury through the miR-30a-5p/LINC01133 axis, which may provide a possible therapeutic method for curing cardiovascular I/R injury.     

MiR-3691-5p is upregulated in docosahexaenoic acid-treated vascular endothelial cell and targets serpin family E member 1

Endothelium, the inner cellular lining of blood vessels, has an important role in the regulation of physiological processes and its dysfunction may initiate cardiovascular complications. Previous investigations have revealed that dietary docosahexaenoic acid (DHA) is related to a lower possibility of cardiovascular disease and mortality. Until now, the molecular mechanisms in the biological activities of DHA remain largely unknown. MicroRNAs (miRNAs) play a vital role in regulating gene expression. Thus, we aimed to investigate whether DHA improves the dysfunction via regulating miRNAs. To understand the protective effects of DHA through modulating miR-3691-5p and its target genes for palmitic acid (PAL) induced apoptosis in endothelial cells. The present study demonstrated that DHA upregulated miR-3691-5p expression, and downregulated the expression of its target gene serpin family E member 1 (SERPINE1). MiR-mimics and inhibitors modulation results indicated that miR-3691-5p regulates endothelial apoptosis through activating antiapoptotic response which controlled by the STAT3 signaling pathway. In conclusion, we have shown that PAL-induced apoptosis could be decreased by DHA treatment through miR-3691-5/SERPINE1 pathways.