Umbilical cord blood exosomes from very preterm infants with bronchopulmonary dysplasia aggravate lung injury in mice.

Bronchopulmonary dysplasia (BPD) is characterized by abnormal development of the blood vessels and alveoli in lungs, which largely occurs in premature infants. Exosomes (EXO) from very preterm infants (VPI) with BPD (BPD-EXO) impair angiogenic activities of human umbilical vein endothelial cells (HUVECs) via EXO-miRNAs cargo. This study aimed to determine whether and how BPD-EXO affect the development of BPD in a mouse model. We showed that treating BPD mice with BPD-EXO chronically and irreversibly aggravated lung injury. BPD-EXO up-regulated 139 and down-regulated 735 genes in the mouse lung tissue. These differentially expressed genes were enriched to the MAPK pathway (e.g., Fgf9 and Cacna2d3), which is critical to angiogenesis and vascular remodeling. BPD-EXO suppressed expression of Fgf9 and Cacna2d3 in HUVECs and inhibited migration, tube formation, and increased cell apoptosis in HUVECs. These data demonstrate that BPD-EXO aggravate lung injury in BPD mice and impair lung angiogenesis, plausibly leading to adverse outcomes of VPI with BPD. These data also suggest that BPD-EXO could serve as promising targets for predicting and treating BPD.

Umbilical cord blood-derived exosomes from healthy term pregnancies protect against hyperoxia-induced lung injury in mice.

Bronchopulmonary dysplasia (BPD) is a chronic, devastating disease primarily occurring in premature infants. To date, intervention strategies to prevent or treat BPD are limited. We aimed to determine the effects of umbilical cord blood-derived exosomes (UCB-EXOs) from healthy term pregnancies on hyperoxia-induced lung injury and to identify potential targets for BPD intervention. A mouse model of hyperoxia-induced lung injury was created by exposing neonatal mice to hyperoxia after birth until the 14th day post birth. Age-matched neonatal mice were exposed to normoxia as the control. Hyperoxia-induced lung injury mice were intraperitoneally injected with UCB-EXO or vehicle daily for 3 days, starting on day 4 post birth. Human umbilical vein endothelial cells (HUVECs) were insulted with hyperoxia to establish an in vitro model of BPD to investigate angiogenesis dysfunction. Our results showed that UCB-EXO alleviated lung injuries in hyperoxia-insulted mice by reducing histopathological grade and collagen contents in the lung tissues. UCB-EXO also promoted vascular growth and increased miR-185-5p levels in the lungs of hyperoxia-insulted mice. Additionally, we found that UCB-EXO elevated miR-185-5p levels in HUVECs. MiR-185-5p overexpression inhibited cell apoptosis, whereas promoted cell migration in HUVECs exposed to hyperoxia. The luciferase reporter assay results revealed that miR-185-5p directly targeted cyclin-dependent kinase 6 (CDK6), which was downregulated in the lungs of hyperoxia-insulted mice. Together, these data suggest that UCB-EXO from healthy term pregnancies protect against hyperoxia-induced lung injuries via promoting neonatal pulmonary angiogenesis partially by elevating miR-185-5p.

A protein encoded by circular ZNF609 RNA induces acute kidney injury by activating the AKT/mTOR-autophagy pathway.

Autophagy plays a crucial role in the development and progression of ischemic acute kidney injury (AKI). However, the function and mechanism of circular RNAs (circRNAs) in the regulation of autophagy in ischemic AKI remain unexplored. Herein, we find that circ-ZNF609, originating from the ZNF609 locus, is highly expressed in the kidney after ischemia/reperfusion injury, and urinary circ-ZNF609 is a moderate predictor for AKI in heart disease patients. Overexpression of circ-ZNF609 can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis while inhibiting proliferation in HK-2 cells, which is blocked by silencing circ-ZNF609. Mechanistically, circ-ZNF609 encodes a functional protein consisting of 250 amino acids (aa), termed ZNF609-250aa, the overexpression of which can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis in HK-2 cells in vitro and in AKI kidneys in vivo. The blockade of AKT and mTOR signaling with pharmacological inhibitors is capable of reversing ZNF609-250aa-induced autophagy flux impairment and cell apoptosis in HK-2 cells. The present study demonstrates that highly expressed circ-ZNF609-encoded ZNF609-250aa induces cell apoptosis and AKI by impairing the autophagy flux via an AKT/mTOR-dependent mechanism. These findings imply that targeting circ-ZNF609 may be a novel therapy for ischemic AKI.

Attenuated Toxoplasma gondii enhances the antitumor efficacy of anti-PD1 antibody by altering the tumor microenvironment in a pancreatic cancer mouse model.

PURPOSE: To investigate whether attenuated Toxoplasma is efficacious against solid tumors of pancreatic cancer and whether attenuated Toxoplasma improves the antitumor activity of αPD-1 antibody on pancreatic cancer. METHODS: The therapeutic effects of attenuated Toxoplasma NRTUA strain monotherapy and combination therapy of NRTUA with anti-PD-1 antibody on PDAC tumor volume and tumor weight of Pan02 tumor-bearing mice were investigated. We characterized the effects of combination therapy of NRTUA with anti-PD-1 antibody on tumor-infiltrating lymphocytes and tumor-specific IFN-γ by using immunohistochemistry, flow cytometry and ELISA. The antitumor mechanisms of combination therapy of NRTUA with anti-PD-1 antibody were investigated via depletion of CD8+ T cells and IL-12. RESULTS: NRTUA strain treatment inhibited tumor growth in a subcutaneous mouse model of PDAC through activating dendritic cells and increasing CD8+ T cell infiltration in the tumor microenvironment. More importantly, combination therapy of NRTUA with anti-PD-1 antibody elicited a significant antitumor immune response and synergistically controlled tumor growth in Pan02 tumor-bearing mice. Specifically, the combination treatment led to elevation of CD8+ T cell infiltration mediated by dendritic cell-secreted IL-12 and to tumor-specific IFN-γ production in the PDAC tumor microenvironment. Also, the combination treatment markedly reduced the immunosuppressive myeloid-derived suppressor cell population in PDAC mice. CONCLUSION: These findings could provide a novel immunotherapy approach to treating solid tumors of PDAC and overcoming resistance to anti-PD-1 agents in PDAC tumors.

DNA N6-methyladenine involvement and regulation of hepatocellular carcinoma development.

DNA N6-methyladenine (6 mA) is a new type of DNA methylation identified in various eukaryotic cells. However, its alteration and genomic distribution features in hepatocellular carcinoma (HCC) remain elusive. In this study, we found that N6AMT1 overexpression increased HCC cell viability, suppressed apoptosis, and enhanced migration and invasion, whereas ALKBH1 overexpression induced the opposite effects. Further, 23,779 gain-of-6 mA regions and 11,240 loss-of-6 mA regions were differentially identified in HCC tissues. The differential gain and loss of 6 mA regions were considerably enriched in intergenic regions. Moreover, 7% of the differential 6 mA modifications were associated with tumors, with 60 associated with oncogenes and 57 with tumor suppressor genes (TSGs), and 17 were common to oncogenes and TSGs. The candidate genes affected by 6 mA were filtered by gene ontology (GO) and RNA-seq. Using quantitative polymerase chain reaction (qPCR), BCL2 and PARTICL were found to be correlated with DNA 6 mA in certain HCC processes.

A Human Proteome Array Approach to Identifying Key Host Proteins Targeted by Toxoplasma Kinase ROP18.

Toxoplasma kinase ROP18 is a key molecule responsible for the virulence of Toxoplasma gondii; however, the mechanisms by which ROP18 exerts parasite virulence via interaction with host proteins remain limited to a small number of identified substrates. To identify a broader array of ROP18 substrates, we successfully purified bioactive mature ROP18 and used it to probe a human proteome array. Sixty eight new putative host targets were identified. Functional annotation analysis suggested that these proteins have a variety of functions, including metabolic process, kinase activity and phosphorylation, cell growth, apoptosis and cell death, and immunity, indicating a pleiotropic role of ROP18 kinase. Among these proteins, four candidates, p53, p38, UBE2N, and Smad1, were further validated. We demonstrated that ROP18 targets p53, p38, UBE2N, and Smad1 for degradation. Importantly, we demonstrated that ROP18 phosphorylates Smad1 Ser-187 to trigger its proteasome-dependent degradation. Further functional characterization of the substrates of ROP18 may enhance understanding of the pathogenesis of Toxoplasma infection and provide new therapeutic targets. Similar strategies could be used to identify novel host targets for other microbial kinases functioning at the pathogen-host interface.