Interferon alpha induction of metallothionein in rat liver is not linked to interleukin-1, interleukin-6, or tumor necrosis factor alpha

Type I Interferons Ameliorate Zinc Intoxication of Candida glabrata by Macrophages and Promote Fungal Immune Evasion

Host and fungal pathogens compete for metal ion acquisition during infectious processes, but molecular mechanisms remain largely unknown. Here, we show that type I interferons (IFNs-I) dysregulate zinc homeostasis in macrophages, which employ metallothionein-mediated zinc intoxication of pathogens as fungicidal response. However, Candida glabrata can escape immune surveillance by sequestering zinc into vacuoles. Interestingly, zinc-loading is inhibited by IFNs-I, because a Janus kinase 1 (JAK1)-dependent suppression of zinc homeostasis affects zinc distribution in macrophages as well as generation of reactive oxygen species (ROS). In addition, systemic fungal infections elicit IFN-I responses that suppress splenic zinc homeostasis, thereby altering macrophage zinc pools that otherwise exert fungicidal actions. Thus, IFN-I signaling inadvertently increases fungal fitness both in vitro and in vivo during fungal infections. Our data reveal an as yet unrecognized role for zinc intoxication in antifungal immunity and suggest that interfering with host zinc homeostasis may offer therapeutic options to treat invasive fungal infections.

Modulation of phospho-proteins by interferon-alpha and valproic acid in acute myeloid leukemia

PURPOSE

Valproic acid (VPA) is suggested to be therapeutically beneficial in combination with interferon-alpha (IFNα) in various cancers. Therefore, we examined IFNα and VPA alone and in combinations in selected AML models, examining immune regulators and intracellular signaling mechanisms involved in phospho-proteomics.

METHODS

The anti-leukemic effects of IFNα and VPA were examined in vitro and in vivo. We mapped the in vitro phosphoprotein modulation by IFNα-2b and human IFNα-Le in MOLM-13 cells by IMAC/2D DIGE/MS analysis and phospho-flow cytometry, and in primary healthy and AML patient-derived PBMCs by CyTOF. In vivo, IFNα-Le and VPA efficacy were investigated in the immunodeficient NOD/Scid IL2γ-/- MOLM-13^Luc+ mouse model and the syngeneic immunocompetent BNML rat model.

RESULTS

IFNα-2b and IFNα-Le differed in the modulation of phospho-proteins involved in protein folding, cell stress, cell death and p-STAT6 Y641, whereas VPA and IFNα-Le shared signaling pathways involving phosphorylation of Akt (T308), ERK1/2 (T202/T204), p38 (T180/Y182), and p53 (S15). Both IFNα compounds induced apoptosis synergistically with VPA in vitro. However, in vivo, VPA monotherapy increased survival, but no benefit was observed by IFNα-Le treatment. CyTOF analysis of primary human PBMCs indicated that lack of immune-cell activation could be a reason for the absence of response to IFNα in the animal models investigated.

CONCLUSIONS

IFNα-2b and IFNα-Le showed potent and synergistic anti-leukemic effects with VPA in vitro but not in leukemic mouse and rat models in vivo. The absence of IFNα immune activation in lymphocyte subsets may potentially explain the limited in vivo anti-leukemic effect of IFNα-monotherapy in AML.

Zinc is a potent and specific inhibitor of IFN-λ3 signalling

Lambda interferons (IFNL, IFN-λ) are pro-inflammatory cytokines important in acute and chronic viral infection. Single-nucleotide polymorphisms rs12979860 and rs8099917 within the IFNL gene locus predict hepatitis C virus (HCV) clearance, as well as inflammation and fibrosis progression in viral and non-viral liver disease. The underlying mechanism, however, is not defined. Here we show that the rs12979860 CC genotype correlates with increased hepatic metallothionein expression through increased systemic zinc levels. Zinc interferes with IFN-λ3 binding to IFNL receptor 1 (IFNLR1), resulting in decreased antiviral activity and increased viral replication (HCV, influenza) in vitro. HCV patients with high zinc levels have low hepatocyte antiviral and inflammatory gene expression and high viral loads, confirming the inhibitory role of zinc in vivo. We provide the first evidence that zinc can act as a potent and specific inhibitor of IFN-λ3 signalling and highlight its potential as a target of therapeutic intervention for IFN-λ3-mediated chronic disease.

Seasonal and spatial comparison of metallothioneins in frog Rana ridibunda from feral populations

The aim of this study was to elucidate the seasonal and spatial regularity of the properties of metallothioneins (MTs) from the liver and kidney of the frog Rana ridibunda in rural (R) and urban (U) sites in Western Ukraine. This allowed examination of their possibility use in biomonitoring of environmental quality. The positive correlation for Zn and negative correlation for Cu were reflected between their content in the liver and MTs. The content of MTs was higher in summer compared to other seasons and also at the U site compare to the R site. MTs had been comprised of two chromatographic forms (MT-1 and MT-2/MT-2a), with lesser and variable MT-2/2a in frogs from the U site, particularly in the kidney. MTs accumulated about 75% of Cd in the liver. In summary, the ability MTs to elevate content as a stress response, together with the sensitivity of MT-2, may be explored to understand the health status of the frog in each season, reflecting the higher overall anthropogenic impact at the U site.

Alterations in the content of metal elements and fatty acids in hepatic ischaemia-reperfusion: induction of apoptotic and necrotic cell death

Ischaemia and reperfusion are related to oxidative stress, which alters with the redox-homeostasis of the liver cells. Our aim was to reveal the correlations between changes of metal element and fatty acid concentration (two main components of redox-balance) and apoptotic and necrotic processes of hepatic ischaemia-reperfusion. Wistar rats were divided into three groups: control, sham-operated and reperfusion. Hepatic ischaemia was induced for 45 min in the left lateral, left medial and right medial lobes followed by 24 h of reperfusion. Global redox parameters and glutathione peroxidase and superoxide dismutase activity were detected by luminometry and spectrophotometry. Routine laboratory measurements, fatty acid composition (with gas chromatography) as well as metal ion concentration of liver (with ICP-OES) were determined. Metallothionein activity was measured by atomic absorption spectrometry. Immunohistochemical and histological examinations were carried out to investigate apoptotic and necrotic changes in the liver. During reperfusion, global antioxidant parameters decreased and superoxide dismutase level of the liver was significantly lower than in the sham-operated group. Changes in the metal element concentration are essential for cellular biochemical pathways, and significant correlations were found between decrease in Cu and Zn content and decreased superoxide dismutase activity. Necrotic lesions along with increased number of apoptotic cells were found in the liver after 24 h of reperfusion. Alterations in the metal element and fatty acid content was found in the liver tissue during 24 h of ischaemia-reperfusion along with increase in the number of apoptotic cells and significant disturbance of the antioxidant balance. Study of the metal element content of the liver during hepatic ischaemia-reperfusion may provide new supportive strategies for liver surgery and transplantation.

Hepatic histologic response (HR) to combination therapy among HCV/HIV-coinfected individuals: interferon induces HR independent of sustained virologic response (SVR)

Most HIV/HCV-coinfected patients fail to achieve a sustained virologic response (SVR) to peginterferon-ribavirin therapy. We examined the hepatic histologic response (HR), defined as an improvement in hepatic inflammation scores of two points or more, to combination therapy among HIV/HCV-coinfected subjects. An open label prospective trial treated 32 HIV/HCV-coinfected patients with peginterferon alpha-2b and ribavirin for 48 weeks. Liver biopsies, scored by a single pathologist using the Histology Activity Index (HAI, range 0-18) and Ishak fibrosis scores (range 0-6), were performed before and after treatment. Gene expression profiles of PBMCs were performed using Affymetrix U133A gene chips. A total of 87% of SVR subjects and 88% of nonresponders (NR) had an HR, but no significant change in the liver fibrosis scores was observed (p > 0.05). For genotype 1 patients, a baseline fibrosis score </=2 was related to a higher likelihood of SVR than those with a score >2 (p = 0.012). Combination therapy for HCV among HIV-coinfected subjects resulted in a modest SVR rate. Persons with mild liver disease had a better SVR rate, suggesting early treatment may be beneficial. Combination therapy resulted in an HR for most of the patients, however, further follow-up of these patients will determine the durability of such an HR.

Interferonbeta-induced changes in metallothionein expression and subcellular distribution of zinc in HepG2 cells

We evaluated the changes of metallothionein induction and cellular zinc distribution in HepG2 cells by interferonbeta treatment. Immunohistochemical staining of metallothionein was observed in the cytoplasm and nuclei of hepatocytes; which was observed predominantly in the cells treated with interferon and zinc compared to those with zinc alone, interferon alone or the no-treated control. The cellular zinc level was higher in order of the interferon- and zinc-treated cells, the zinc-alone-treated cells, and the interferon-alone-treated cells. Flow cytometry showed that S-phase population increased in interferon-alone-treated cells and interferon- and zinc-treated cells, but not in zinc-alone-treated ones. Cellular elemental distribution was analyzed using in-air micro-particle induced X-ray emission. In zinc-alone-treated sample, X-ray spectra showed good consistency between the enhanced cellular zinc distribution and the phosphorous map. Localizations of bromine followed by interferon treatment were found accompanying a spatial correlation with the phosphorous map. The samples treated with interferon and zinc showed the marked accumulation of zinc and bromine. Discrete bromine accumulation sites were clearly visible with a strong spatial correlation followed by zinc accumulation. These findings suggest that interferonbeta in combination with zinc predominantly induces metallothionein expression in HepG2 cells. In addition, interferonbeta may promote the translocation of metallothionein-bound zinc from cytoplasm to S-phase nuclei.