Pro-apoptotic Noxa is involved in ablative focal irradiation-induced lung injury

Development of a novel tool for high-precision focal irradiation using a clinical brachytherapy system

PURPOSE

This study aims to emphasize the necessity of a focal irradiation tool for small animals and compare the beam characteristics of a tool developed using a brachytherapy system with a linear accelerator (LINAC)-based tool.

METHODS

A 1-mm tungsten collimator was designed for a Ir-192 brachytherapy system. The percent depth dose (PDD) and horizontal profile of the collimator were measured and compared with a 4-mm commercial cone in the LINAC. Monte Carlo simulations validated all the measurements. Mouse brains were irradiated using a focal irradiation tool, and immunohistochemistry was performed on the brain samples to assess the dose accuracy.

RESULTS

PDD showed that the maximum dose (dmax) for Ir-192 was at the surface in both measurements and simulations. At a depth of 1 mm, the collimator measured doses of 25.6 % and 21.0 %, respectively. At 6 MV in the LINAC, the dmax was observed at depths of 0.7 and 0.8 cm in measurements and simulations, respectively. The full width at half maximum (FWHM) at a depth of 1 mm was 1.0 and 1.1 mm for Ir-192 in the measurements and simulations, respectively. For small cone sizes at dmax, FWHM was 4.0 and 4.1 mm for the measurements and simulations, respectively. Immunohistochemistry results indicated that focal irradiation with Ir-192 affected small superficial brain areas while sparing the contralateral side and subventricular zone.

CONCLUSION

The focal irradiation tool accurately delivered doses to small regions and shallow depths in the mouse brain, making it valuable for precise radiotherapy during small animal experiments.

Identification of the shared genes and immune signatures between systemic lupus erythematosus and idiopathic pulmonary fibrosis

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disorder which could lead to inflammation and fibrosis in various organs. Pulmonary fibrosis is a severe complication in patients with SLE. Nonetheless, SLE-derived pulmonary fibrosis has unknown pathogenesis. Of pulmonary fibrosis, Idiopathic pulmonary fibrosis (IPF) is a typicality and deadly form. Aiming to investigate the gene signatures and possible immune mechanisms in SLE-derived pulmonary fibrosis, we explored common characters between SLE and IPF from Gene Expression Omnibus (GEO) database.

RESULTS

We employed the weighted gene co-expression network analysis (WGCNA) to identify the shared genes. Two modules were significantly identified in both SLE and IPF, respectively. The overlapped 40 genes were selected out for further analysis. The GO enrichment analysis of shared genes between SLE and IPF was performed with ClueGO and indicated that p38MAPK cascade, a key inflammation response pathway, may be a common feature in both SLE and IPF. The validation datasets also illustrated this point. The enrichment analysis of common miRNAs was obtained from the Human microRNA Disease Database (HMDD) and the enrichment analysis with the DIANA tools also indicated that MAPK pathways' role in the pathogenesis of SLE and IPF. The target genes of these common miRNAs were identified by the TargetScan7.2 and a common miRNAs-mRNAs network was constructed with the overlapped genes in target and shared genes to show the regulated target of SLE-derived pulmonary fibrosis. The result of CIBERSORT showed decreased regulatory T cells (Tregs), naïve CD4+ T cells and rest mast cells but increased activated NK cells and activated mast cells in both SLE and IPF. The target genes of cyclophosphamide were also obtained from the Drug Repurposing Hub and had an interaction with the common gene PTGS2 predicted with protein-protein interaction (PPI) and molecular docking, indicating its potential treatment effect.

CONCLUSIONS

This study originally uncovered the MAPK pathway, and the infiltration of some immune-cell subsets might be pivotal factors for pulmonary fibrosis complication in SLE, which could be used as potentially therapeutic targets. The cyclophosphamide may treat SLE-derived pulmonary fibrosis through interaction with PTGS2, which could be activated by p38MAPK.

Intercellular transfer of miR-200c-3p impairs the angiogenic capacity of cardiac endothelial cells

As mediators of intercellular communication, extracellular vesicles containing molecular cargo such as microRNAs, are secreted by cells and taken up by recipient cells to influence their cellular phenotype and function. Here, we report that cardiac stress-induced differential microRNA content, with miR-200c-3p being one of the most enriched, in cardiomyocyte-derived extracellular vesicles mediates functional crosstalk with endothelial cells. Silencing of miR-200c-3p in mice subjected to chronic increased cardiac pressure overload resulted in attenuated hypertrophy, smaller fibrotic areas, higher capillary density and preserved cardiac ejection fraction. Interestingly, we were able to maximal rescue microvascular and cardiac function with very low doses of antagomir, which specifically silences miR-200c-3p expression in the non-myocyte cells. Our results reveal vesicle transfer of miR-200c-3p from cardiomyocytes to cardiac endothelial cells, underlining the importance of cardiac intercellular communication in the pathophysiology of heart failure.

Vitamin D Receptor Protects against Radiation-Induced Intestinal Injury in Mice via Inhibition of Intestinal Crypt Stem/Progenitor Cell Apoptosis

It is urgent to seek new potential targets for the prevention or relief of gastrointestinal syndrome in clinical radiation therapy for cancers. Vitamin D, mediated through the vitamin D receptor (VDR), has been identified as a protective nutrient against ionizing radiation (IR)-induced damage. This study investigated whether VDR could inhibit IR-induced intestinal injury and explored underlying mechanism. We first found that vitamin D induced VDR expression and inhibited IR-induced DNA damage and apoptosis in vitro. VDR was highly expressed in intestinal crypts and was critical for crypt stem/progenitor cell proliferation under physiological conditions. Next, VDR-deficient mice exposed to IR significantly increased DNA damage and crypt stem/progenitor cell apoptosis, leading to impaired intestinal regeneration as well as shorter survival time. Furthermore, VDR deficiency activated the Pmaip1-mediated apoptotic pathway of intestinal crypt stem/progenitor cells in IR-treated mice, whereas inhibition of Pmaip1 expression by siRNA transfection protected against IR-induced cell apoptosis. Therefore, VDR protects against IR-induced intestinal injury through inhibition of crypt stem/progenitor cell apoptosis via the Pmaip1-mediated pathway. Our results reveal the importance of VDR level in clinical radiation therapy, and targeting VDR may be a useful strategy for treatment of gastrointestinal syndrome.

Cellular microRNAs influence replication of H3N2 canine influenza virus in infected cells

MicroRNAs (miRNAs) are known to play important regulatory roles in host-virus interactions. Avian-origin H3N2 canine influenza virus (CIV) has emerged as the most prevalent subtype among dogs in Asia since 2007. To evaluate the roles of host miRNAs in H3N2 CIV infection, here, miRNA profiles obtained from primary canine bronchiolar epithelial cells (CBECs) and canine alveolar macrophages (CAMCs) were compared between infected and mock-infected cells with the H3N2 CIV JS/10. It was found that the expressions of cfa-miR-125b and cfa-miR-151, which have been reported to be associated with innate immunity and inflammatory response, were significantly decreased in CIV-infected canine primary cells. Bioinformatics prediction indicated that 5' seed regions of the two miRNAs are partially complementary to the mRNAs of nucleoprotein (NP) and non-structural protein 1 (NS1) of JS/10. As determined by virus titration, quantitative real-time PCR (qRT-PCR) and western blotting, overexpression of the two miRNAs inhibited CIV replication in cell culture, while their inhibition facilitated this replication, suggesting that the two miRNAs could act as negative regulators of CIV replication. Our findings support the notion that some cellular miRNAs can influence the outcome of virus infection, which helps to elucidate the resistance of host cells to viral infection and to clarify the pathogenesis of H3N2 CIV.

PM014 attenuates radiation-induced pulmonary fibrosis via regulating NF-kB and TGF-b1/NOX4 pathways

Radiation therapy is the mainstay in the treatment of lung cancer, and lung fibrosis is a radiotherapy-related major side effect that can seriously reduce patient’s quality of life. Nevertheless, effective strategies for protecting against radiation therapy-induced fibrosis have not been developed. Hence, we investigated the radioprotective effects and the underlying mechanism of the standardized herbal extract PM014 on radiation-induced lung fibrosis. Ablative radiation dose of 75 Gy was focally delivered to the left lung of mice. We evaluated the effects of PM014 on radiation-induced lung fibrosis in vivo and in an in vitro model. Lung volume and functional changes were evaluated using the micro-CT and flexiVent system. Fibrosis-related molecules were evaluated by immunohistochemistry, western blot, and real-time PCR. A orthotopic lung tumour mouse model was established using LLC1 cells. Irradiated mice treated with PM014 showed a significant improvement in collagen deposition, normal lung volume, and functional lung parameters, and these therapeutic effects were better than those of amifostine. PM104 attenuated radiation-induced increases in NF-κB activity and inhibited radiation-induced p65 translocation, ROS production, DNA damage, and epithelial-mesenchymal transition. PM104 effectively alleviated fibrosis in an irradiated orthotopic mouse lung tumour model while not attenuating the efficacy of the radiation therapy by reduction of the tumour. Standardized herbal extract PM014 may be a potential therapeutic agent that is able to increase the efficacy of radiotherapy by alleviating radiation-induced lung fibrosis.

Crosstalk between Noxa, Bcl-2, and ceramide in mediating p53-dependent apoptosis in Molt-4 human T-cell leukemia

Ionizing radiation induces apoptosis in human Molt-4 leukemia cells in a p53-dependent manner. The tumor suppressor p53 stimulates various downstream targets that presumably trigger, individually or in concert, de novo ceramide synthesis and intrinsic apoptosis via mitochondrial outer membrane permeabilization (MOMP). Among these targets, BH3-only protein Noxa was found to be promptly activated by p53 prior to ceramide accumulation and apoptosis in response to irradiation. To evaluate the relation between Noxa and ceramide in irradiation-induced apoptosis, Noxa was silenced in Molt-4 cells and apoptosis, p53 expression, and ceramide accumulation were assessed in response to irradiation. In the absence of Noxa, irradiation of Molt-4 cells still induced apoptosis in a p53-dependent manner however ceramide levels decreased significantly although they remained higher than untreated control. Upon irradiation, Noxa was found to translocate to the mitochondria where endogenous ceramide accumulation was observed. In contrast, overexpression of Bcl-2, another mitochondrial protein, in Molt-4 cells abolished the endogenous ceramide accumulation and apoptosis. In irradiation-induced, p53-dependent pathways of apoptosis, the pro-apoptotic Noxa represents one of several, yet to be identified, pathways simultaneously triggered by p53 to produce mitochondrial ceramide accumulation and apoptosis. In contrast, Bcl-2 functions as a broader inhibitor of both ceramide accumulation and apoptosis. Altogether, these results indicate that members of the Bcl-2 family differentially regulate ceramide accumulation and reveal the existence of crosstalk between Bcl-2 family members and ceramide in mediating p53-dependent apoptosis in Molt-4 human T-cell leukemia.

Ferroptosis Is Involved in Diabetes Myocardial Ischemia/Reperfusion Injury Through Endoplasmic Reticulum Stress

Myocardial ischemic disease affects the prognosis in perioperative patients. Diabetes can aggravate myocardial injury. The purpose of this research is to investigate the effect of ferroptosis in the process of diabetes mellitus (DM) myocardial ischemia/reperfusion (I/R) injury (IRI). Endoplasmic reticulum stress (ERS) is investigated whether aggravates cardiomyocytes injury. Rat DM+I/R (DIR), cell high glucose (HG), hypoxia reoxygenation (H/R), and high-glucose H/R (HH/R) models were established. Ferroptosis inhibitor Ferrostatin-1, ferroptosis agonist Erastin, ERS inhibitor Salubrinal, and ERS agonist Tunicamycin were administered. Serum creatine kinase-MB (CK-MB), cell viability, lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), reactive oxygen species (ROS), and cellular ferrous ion concentration were examined. The level of ACSL4, GPX4, ATF4, CHOP, BCL-2, and BAX was detected. Myocardial tissue pathological change was detected by hematoxylin-eosin staining. Cardiac function was monitored by invasive hemodynamic measurements. Evans Blue-triphenyltetrazolium chloride double staining was used to detect the myocardial infarct size. In DM+sham (DS) (or HG) and I/R (or H/R) models, cardiomyocytes were injured accompanied by increased level of ferroptosis and ERS. Moreover, the cell injury was more serious in rat DIR or cell HH/R models. Inhibition of ferroptosis in DIR model could reduce ERS and myocardial injury. Inhibition of ferroptosis in H9c2 cells HG, H/R, and HH/R models could reduce cell injury. Erastin could aggravate ERS and cell injury by stimulating ferroptosis in HH/R cell model. Meanwhile, inhibition of ERS could alleviate ferroptosis and cell injury. Ferroptosis is involved in DIR injury that is related to ERS. Moreover, inhibition of ferroptosis can alleviate DIR injury, which may provide a therapeutic regent for myocardial ischemic disease.

Effects of retinoic acid-inducible gene-I-like receptors activations and ionizing radiation cotreatment on cytotoxicity against human non-small cell lung cancer in vitro

Retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) are pattern-recognition receptors that recognize pathogen-associated molecular patterns and induce antiviral immune responses. Recent studies have demonstrated that RLR activation induces antitumor immunity and cytotoxicity against different types of cancer, including lung cancer. However a previous report has demonstrated that ionizing radiation exerts a limited effect on RLR in human monocytic cell-derived macrophages, suggesting that RLR agonists may be used as effective immunostimulants during radiation therapy. However, it is unclear whether ionizing radiation affects the cytotoxicity of RLR agonists against cancer cells. Therefore, in the present study the effects of cotreatment with ionizing radiation and RLR agonists on cytotoxicity against human non-small cell lung cancer cells A549 and H1299 was investigated. Treatment with RLR agonist poly(I:C)/LyoVec™ [poly(I:C)] exerted cytotoxic effects against human non-small cell lung cancer. The cytotoxic effects of poly(I:C) were enhanced by cotreatment with ionizing radiation, and poly(I:C) pretreatment resulted in the radiosensitization of non-small cell lung cancer. Furthermore, cotreatment of A549 and H1299 cells with poly(I:C) and ionizing radiation effectively induced apoptosis in a caspase-dependent manner compared with treatment with poly(I:C) or ionizing radiation alone. These results indicate that RLR agonists and ionizing radiation cotreatment effectively exert cytotoxic effects against human non-small cell lung cancer through caspase-mediated apoptosis.