Interferon-γ regulates cell malignant growth via the c-Abl/HDAC2 signaling pathway in mammary epithelial cells

Carnosine Synthase 1 Contributes to Interferon Gamma-Induced Arginine Depletion via Mitogen-activated Protein Kinase 11 Signaling in Bovine Mammary Epithelial Cells

Arginine is one of the host semiessential amino acids with diverse biological activities, and arginine depletion is associated with the incidence of many diseases. Arginine depletion induced by diet-derived interferon gamma (IFN-γ) leads to malignant transformation and impaired milk quality in healthy lactating bovine mammary epithelial cells (BMECs). However, the molecular mechanism of IFN-γ-induced arginine depletion is unclear. In this study, the BMEC cell line, mammary alveolar cells-large T antigen cells (MAC-T), was stimulated with IFN-γ (10 ng/mL) for 24 h, and cellular arginine and ornithine quantified by liquid chromatography-tandem mass spectrometry. Carnosine synthase 1 (CARNS1) was identified from RNA-seq data, CARNS1 knockdown was achieved using an shRNA interfering plasmid. The expression levels of CARNS1, argininosuccinate synthetase 1 (ASS1), mitogen-activated protein kinase 11 (p38 MAPK), and phosphorylated (p)-p38, and their cognate genes, were analyzed by Western blotting and real-time quantitative polymerase chain reaction. The results showed that IFN-γ inhibited the biosynthesis of arginine, but enhanced its catalysis via disruption of key enzymes involved in arginine metabolism. IFN-γ also inhibited the expression of CARNS1, ASS1, and cationic amino acid transporter 1, while activating the expression and phosphorylation of p38. However, knockdown of CARNS1 reduced arginine level and ASS1 expression and block of either the IFN-γ receptor IFN-γ receptor 2 or p38 relieved both the expression of Carnosine synthase 1 (CARNS1) and ASS1. In summary, these results indicate that IFN-γ induced arginine depletion through inhibition of CARNS1 signaling via activation of p38 in BMECs. These findings provide a novel insight for IFN-γ-related disease control strategies in dairy cows.

Porcine Deltacoronavirus Infection Cleaves HDAC2 to Attenuate Its Antiviral Activity

Protein acetylation plays an important role during virus infection. Thus, it is not surprising that viruses always evolve elaborate mechanisms to regulate the functions of histone deacetylases (HDACs), the essential transcriptional and epigenetic regulators for deacetylation. Porcine deltacoronavirus (PDCoV), an emerging enteropathogenic coronavirus, causes severe diarrhea in suckling piglets and has the potential to infect humans. In this study, we found that PDCoV infection inhibited cellular HDAC activity. By screening the expressions of different HDAC subfamilies after PDCoV infection, we unexpectedly found that HDAC2 was cleaved. Ectopic expression of HDAC2 significantly inhibited PDCoV replication, while the reverse effects could be observed after treatment with an HDAC2 inhibitor (CAY10683) or the knockdown of HDAC2 expression by specific siRNA. Furthermore, we demonstrated that PDCoV-encoded nonstructural protein 5 (nsp5), a 3C-like protease, was responsible for HDAC2 cleavage through its protease activity. Detailed analyses showed that PDCoV nsp5 cleaved HDAC2 at glutamine 261 (Q261), and the cleaved fragments (amino acids 1 to 261 and 262 to 488) lost the ability to inhibit PDCoV replication. Interestingly, the Q261 cleavage site is highly conserved in HDAC2 homologs from other mammalian species, and the nsp5s encoded by seven tested mammalian coronaviruses also cleaved HDAC2, suggesting that cleaving HDAC2 may be a common strategy used by different mammalian coronaviruses to antagonize the antiviral role of HDAC2. IMPORTANCE As an emerging porcine enteropathogenic coronavirus that possesses the potential to infect humans, porcine deltacoronavirus (PDCoV) is receiving increasing attention. In this work, we found that PDCoV infection downregulated cellular histone deacetylase (HDAC) activity. Of particular interest, the viral 3C-like protease, encoded by the PDCoV nonstructural protein 5 (nsp5), cleaved HDAC2, and this cleavage could be observed in the context of PDCoV infection. Furthermore, the cleavage of HDAC2 appears to be a common strategy among mammalian coronaviruses, including the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), to antagonize the antiviral role of HDAC2. To our knowledge, PDCoV nsp5 is the first identified viral protein that can cleave cellular HDAC2. Results from our study provide new targets to develop drugs combating coronavirus infection.

LAP3 contributes to IFN-γ-induced arginine depletion and malignant transformation of bovine mammary epithelial cells

BACKGROUND

IFN-γ has been traditionally recognized as an inflammatory cytokine that involves in inflammation and autoimmune diseases. Previously we have shown that sustained IFN-γ induced malignant transformation of bovine mammary epithelial cells (BMECs) via arginine depletion. However, the molecular mechanism underlying this is still unknown.

METHODS

In this study, the amino acids contents in BMECs were quantified by a targeted metabolomics method. The acquisition of differentially expressed genes was mined from RNA-seq dataset and analyzed bioinformatically. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), western blotting, and immunohistochemistry (IHC) assay were performed to detect gene mRNA and protein expression levels. CCK-8 and would healing assays were used to detect cell proliferation and migration abilities, respectively. Cell cycle phase alternations were analyzed by flow cytometry.

RESULTS

The targeted metabolomics analysis specifically discovered IFN-γ induced arginine depletion through accelerating arginine catabolism and inhibiting arginine anabolism in BMECs. Transcriptome analysis identified leucine aminopeptidase 3 (LAP3), which was regulated by p38 and ERK MAPKs, to downregulate arginine level through interfering with argininosuccinate synthetase (ASS1) as IFN-γ stimulated. Moreover, LAP3 also contributed to IFN-γ-induced malignant transformation of BMECs by upregulation of HDAC2 (histone deacetylase 2) expression and promotion of cell cycle proteins cyclin A1 and D1 expressions. Arginine supplementation did not affect LAP3 and HDAC2 expressions, but slowed down cell cycle process of malignant BMECs. In clinical samples of patients with breast cancer, LAP3 was confirmed to be upregulated, while ASS1 was downregulated compared with healthy control.

CONCLUSIONS

These results demonstrated that LAP3 mediated IFN-γ-induced arginine depletion to malignant transformation of BMECs. Our findings provide a potential therapeutic target for breast cancer both in humans and dairy cows.

MicroRNA-122-5p prevents proliferation and promotes apoptosis of hepatic stellate cells by suppressing the cellular-Abelsongene/histone deacetylases 2 pathway

Liver fibrosis is a wound-healing response and the activation of the hepatic stellate cell (HSC) is the core of hepatic fibrosis. MicroRNAs (miRNAs) participate in the development of fibrosis. It is reported that histone deacetylases (HDAC2) tyrosine phosphorylation by cellular-Abelsongene (c-Abl) induces malignant growth of cells. Here, we investigated the effect of miR-122-5p on the proliferation and apoptosis of HSCs. Normal human HSC line LX-2 and LX-2 cells stimulated by transforming growth factor (TGF)-β1 for 24 h were cultured and assigned into the blank group and the TGF-β1 group. The miR-122-5p inhibitor and its negative control were transfected into LX-2 cells and miR-122-5p mimic and its negative control were transfected into LX-2 cells stimulated by TGF-β1. The result showed that miR-122-5p expression was decreased in TGF-β1-stimulated LX-2 cells. miR-122-5p overexpression reduced the mRNA and protein levels of collagen I and α-smooth muscle actin, inhibited cell proliferation, and accelerated cell apoptosis. miR-122-5p targeted c-Abl. Meanwhile, miR-122-5p overexpression inhibited HSC activation by suppressing the c-Abl/HDAC2 pathway. In summary, miR-122-5p overexpression exerted anti-fibrosis effect and inhibited HSC activation by suppressing the c-Abl/HDAC2 pathway.

RGFP966 inactivation of the YAP pathway attenuates cardiac dysfunction induced by prolonged hypothermic preservation

Oxidative stress and apoptosis are the key factors that limit the hypothermic preservation time of donor hearts to within 4-6 h. The aim of this study was to investigate whether the histone deacetylase 3 (HDAC3) inhibitor RGFP966 could protect against cardiac injury induced by prolonged hypothermic preservation. Rat hearts were hypothermically preserved in Celsior solution with or without RGFP966 for 12 h followed by 60 min of reperfusion. Hemodynamic parameters during reperfusion were evaluated. The expression and phosphorylation levels of mammalian STE20-like kinase-1 (Mst1) and Yes-associated protein (YAP) were determined by western blotting. Cell apoptosis was measured by the terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) method. Addition of RGFP966 in Celsior solution significantly inhibited cardiac dysfunction induced by hypothermic preservation. RGFP966 inhibited the hypothermic preservation-induced increase of the phosphorylated (p)-Mst1/Mst1 and p-YAP/YAP ratios, prevented a reduction in total YAP protein expression, and increased the nuclear YAP protein level. Verteporfin (VP), a small molecular inhibitor of YAP-transcriptional enhanced associate domain (TEAD) interaction, partially abolished the protective effect of RGFP966 on cardiac function, and reduced lactate dehydrogenase activity and malondialdehyde content. RGFP966 increased superoxide dismutase, catalase, and glutathione peroxidase gene and protein expression, which was abolished by VP. RGFP966 inhibited hypothermic preservation-induced overexpression of B-cell lymphoma protein 2 (Bcl-2)-associated X (Bax) and cleaved caspase-3, increased Bcl-2 mRNA and protein expression, and reduced cardiomyocyte apoptosis. The antioxidant and anti-apoptotic effects of RGFP966 were cancelled by VP. The results suggest that supplementation of Celsior solution with RGFP966 attenuated prolonged hypothermic preservation-induced cardiac dysfunction. The mechanism may involve inhibition of oxidative stress and apoptosis via inactivation of the YAP pathway.

Carfilzomib inhibits the growth of lung adenocarcinoma via upregulation of Gadd45a expression

Proteasome inhibitors have shown remarkable success in the treatment of hematologic neoplasm. There has been a lot of attention to applying these drugs for solid tumor treatment. Recent preclinical study has signified the effectiveness on cell proliferation inhibition in lung adenocarcinoma treated by carfilzomib (CFZ), a second generation proteasome inhibitor. However, no insight has been gained regarding the mechanism. In this study, we have systematically investigated the CFZ functions in cell proliferation and growth, cell cycle arrest, and apoptosis in lung adenocarcinoma cells. Flow cytometry experiments showed that CFZ significantly induced G2/M cell cycle arrest and apoptosis in lung adenocarcinoma. MTS and colony formation assays revealed that CFZ substantially inhibited survival of lung adenocarcinoma cells. All results were consistently correlated to the upregulation expression of Gadd45a, which is an important gene in modulating cell cycle arrest and apoptosis in response to physiologic and environmental stresses. Here, upregulation of Gadd45a expression was observed after CFZ treatment. Knocking down Gadd45a expression suppressed G2/M arrest and apoptosis in CFZ-treated cells, and reduced cytotoxicity of this drug. The protein expression analysis has further identified that the AKT/FOXO3a pathway is involved in Gadd45a upregulation after CFZ treatment. These findings unveil a novel mechanism of proteasome inhibitor in anti-solid tumor activity, and shed light on novel preferable therapeutic strategy for lung adenocarcinoma. We believe that Gadd45a expression can be a highly promising candidate predictor in evaluating the efficacy of proteasome inhibitors in solid tumor therapy.

Interferon-α2b spray inhalation did not shorten virus shedding time of SARS-CoV-2 in hospitalized patients: a preliminary matched case-control study

BACKGROUND

Currently, there are no drugs that have been proven to be effective against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Because of its broad antiviral activity, interferon (IFN) should be evaluated as a potential therapeutic agent for treatment of coronavirus disease 2019 (COVID-19), especially while COVID-19-specific therapies are still under development.

METHODS

Confirmed COVID-19 patients hospitalized in the First Affiliated Hospital, School of Medicine, Zhejiang University in Hangzhou, China, from January 19 to February 19, 2020 were enrolled in a retrospective study. The patients were separated into an IFN group and a control group according to whether they received initial IFN-α2b inhalation treatment after admission. Propensity-score matching was used to balance the confounding factors.

RESULTS

A total of 104 confirmed COVID-19 patients, 68 in the IFN group and 36 in the control group, were enrolled. Less hypertension (27.9% vs. 55.6%, P=0.006), dyspnea (8.8% vs. 25.0%, P=0.025), or diarrhea (4.4% vs. 19.4%, P=0.030) was observed in the IFN group. Lower levels of albumin and C-reactive protein and higher level of sodium were observed in the IFN group. Glucocorticoid dosage was lower in the IFN group (median, 40 vs. 80 mg/d, P=0.025). Compared to the control group, fewer patients in the IFN group were ventilated (13.2% vs. 33.3%, P=0.015) and admitted to intensive care unit (ICU) (16.2% vs. 44.4%, P=0.002). There were also fewer critical patients in the IFN group (7.4% vs. 25.0%, P=0.017) upon admission. Although complications during admission process were comparable between groups, the discharge rate (85.3% vs. 66.7%, P=0.027) was higher and the hospitalization time (16 vs. 21 d, P=0.015) was shorter in the IFN group. When other confounding factors were not considered, virus shedding time (10 vs. 13 d, P=0.014) was also shorter in the IFN group. However, when the influence of other factors was eliminated using propensity score matching, virus shedding time was not significantly shorter than that of the control group (12 vs. 15 d, P=0.206).

CONCLUSIONS

IFN-α2b spray inhalation did not shorten virus shedding time of SARS-CoV-2 in hospitalized patients.

Ubiquitin-like modifier-activating enzyme 7 as a marker for the diagnosis and prognosis of breast cancer

Ubiquitin-like modifier-activating enzyme 7 (UBA7) is a specific E1-like ubiquitin-activating enzyme involved in interferon-stimulated gene 15 (ISG15) conjugation. UBA7 expression has been reported to be notably decreased in lung cancer. The present study aimed to investigate the changes in UBA7 expression in breast cancer and the association between UBA7 expression and clinical characteristics, and to elucidate the diagnostic and prognostic significance of UBA7 in breast cancer. The clinical data and RNA-sequencing expression values of 1,104 patients with breast cancer were downloaded from The Cancer Genome Atlas database. The associations between UBA7 expression and clinical characteristics were determined using χ2 and Fisher's exact tests. UBA7 expression values were divided into low and high groups using the optimal cut-off value, as determined by the overall survival (OS) value identified via a receiver operating characteristic (ROC) curve analysis, to further study the association between UBA7 expression and clinical characteristics. The diagnostic capability of UBA7 was assessed via ROC analysis, and Kaplan-Meier curve and Cox regression analyses were performed to determine the prognostic value of UBA7. The results demonstrated that UBA7 expression was decreased in breast cancer, and significant differences were observed between groups with regards to vital status, tumor classification, metastasis classification, histological type, sex, molecular subtype, and expression levels of progesterone receptor, estrogen receptor (ER) and human epidermal growth factor receptor 2. Low and high UBA7 expression levels were associated with age, ER expression, menopause status, Tumor-Node-Metastasis classification stage, margin status, vital status, radiation therapy use, OS and relapse-free survival. Furthermore, patients with low UBA7 expression levels had a poor prognosis. UBA7 expression also demonstrated an ability to diagnose patients at all clinical stages. Taken together, the results indicated that UBA7 expression was significantly decreased in breast cancer, and was associated with clinical characteristics and prognosis. Thus, UBA7 can be deemed as a potential biomarker in breast cancer, and may serve as a target in treatment.

IFN-γ drives inflammatory bowel disease pathogenesis through VE-cadherin-directed vascular barrier disruption

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with rising incidence. Diseased tissues are heavily vascularized. Surprisingly, the pathogenic impact of the vasculature in IBD and the underlying regulatory mechanisms remain largely unknown. IFN-γ is a major cytokine in IBD pathogenesis, but in the context of the disease, it is almost exclusively its immune-modulatory and epithelial cell-directed functions that have been considered. Recent studies by our group demonstrated that IFN-γ also exerts potent effects on blood vessels. Based on these considerations, we analyzed the vessel-directed pathogenic functions of IFN-γ and found that it drives IBD pathogenesis through vascular barrier disruption. Specifically, we show that inhibition of the IFN-γ response in vessels by endothelial-specific knockout of IFN-γ receptor 2 ameliorates experimentally induced colitis in mice. IFN-γ acts pathogenic by causing a breakdown of the vascular barrier through disruption of the adherens junction protein VE-cadherin. Notably, intestinal vascular barrier dysfunction was also confirmed in human IBD patients, supporting the clinical relevance of our findings. Treatment with imatinib restored VE-cadherin/adherens junctions, inhibited vascular permeability, and significantly reduced colonic inflammation in experimental colitis. Our findings inaugurate the pathogenic impact of IFN-γ-mediated intestinal vessel activation in IBD and open new avenues for vascular-directed treatment of this disease.

Interferon gamma induces inflammatory responses through the interaction of CEACAM1 and PI3K in airway epithelial cells

BACKGROUND

Interferon gamma (IFNγ) plays an important role in the development of chronic lung diseases via the production of inflammatory mediators, although the exact mechanism remains unclear. The present study aimed at investigating the potential mechanisms by which IFNγ induced over-production of interleukins through the interaction between carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway.

METHODS

IFN-γ induced over-production of interleukin (IL) 6 and IL8, and RNA expression of CEACAM1 and its subtypes or PI3K and its subtypes in human bronchial epithelial cells (HBE). The production of IL6 and IL8 or cell proliferation and movement were also evaluated in cell^CEACAM1- or cell^CEACAM1+ after the induction of IFN-γ. Roles of PI3K subtype proteins, e.g. PI3Kp110α/δ, Akt, p110α/γ/δ/β/mTOR, PI3Kp110α/δ/β, PI3Kp110δ, or pan-PI3K in IFN-γ-induced CEACAM1 subtype alterations were furthermore validated using those proteins of PI3K subtypes.

RESULTS

CEACAM1, especially CEACAM1-S isoforms, was significantly up-regulated in HBE cells after treatment with IFN-γ. CEACAM1 played roles in expression of IL-6 and IL-8, and facilitated cellular proliferation and migration. IFN-γ up-regulated the expression of CEACAM1 in airway epithelial cells, especially CEACAM1-S isoforms, promoting cellular proliferation, migration, and the production of inflammatory factors. PI3K (p110δ)/Akt/mTOR pathway was involved in the process of IFN-γ-upregulated CEACAM1, especially CEACAM1-S. On the other hand, CEACAM1 could promote the activation of PI3K/Akt/mTOR pathway.

CONCLUSION

IFN-γ could induce inflammatory responses, cellular growth and proliferation through the interaction of CEACAM1 (especially CEACAM1-S isoforms) and PI3K(p110δ)/Akt/mTOR in airway epithelial cells, which might be new alternative of future therapies against epithelial transition from inflammation to cancer.