The expression of Mirc1/Mir17-92 cluster in sputum samples correlates with pulmonary exacerbations in cystic fibrosis patients

INTRODUCTION

Cystic fibrosis (CF) is a multi-organ disorder characterized by chronic sino-pulmonary infections and inflammation. Many patients with CF suffer from repeated pulmonary exacerbations that are predictors of worsened long-term morbidity and mortality. There are no reliable markers that associate with the onset or progression of an exacerbation or pulmonary deterioration. Previously, we found that the Mirc1/Mir17-92a cluster which is comprised of 6 microRNAs (Mirs) is highly expressed in CF mice and negatively regulates autophagy which in turn improves CF transmembrane conductance regulator (CFTR) function. Therefore, here we sought to examine the expression of individual Mirs within the Mirc1/Mir17-92 cluster in human cells and biological fluids and determine their role as biomarkers of pulmonary exacerbations and response to treatment.

METHODS

Mirc1/Mir17-92 cluster expression was measured in human CF and non-CF plasma, blood-derived neutrophils, and sputum samples. Values were correlated with pulmonary function, exacerbations and use of CFTR modulators.

RESULTS

Mirc1/Mir17-92 cluster expression was not significantly elevated in CF neutrophils nor plasma when compared to the non-CF cohort. Cluster expression in CF sputum was significantly higher than its expression in plasma. Elevated CF sputum Mirc1/Mir17-92 cluster expression positively correlated with pulmonary exacerbations and negatively correlated with lung function. Patients with CF undergoing treatment with the CFTR modulator Ivacaftor/Lumacaftor did not demonstrate significant change in the expression Mirc1/Mir17-92 cluster after six months of treatment.

CONCLUSIONS

Mirc1/Mir17-92 cluster expression is a promising biomarker of respiratory status in patients with CF including pulmonary exacerbation.

Elevated Mirc1/Mir17-92 cluster expression negatively regulates autophagy and CFTR (cystic fibrosis transmembrane conductance regulator) function in CF macrophages

Cystic fibrosis (CF) is a fatal, genetic disorder that critically affects the lungs and is directly caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in defective CFTR function. Macroautophagy/autophagy is a highly regulated biological process that provides energy during periods of stress and starvation. Autophagy clears pathogens and dysfunctional protein aggregates within macrophages. However, this process is impaired in CF patients and CF mice, as their macrophages exhibit limited autophagy activity. The study of microRNAs (Mirs), and other noncoding RNAs, continues to offer new therapeutic targets. The objective of this study was to elucidate the role of Mirs in dysregulated autophagy-related genes in CF macrophages, and then target them to restore this host-defense function and improve CFTR channel function. We identified the Mirc1/Mir17-92 cluster as a potential negative regulator of autophagy as CF macrophages exhibit decreased autophagy protein expression and increased cluster expression when compared to wild-type (WT) counterparts. The absence or reduced expression of the cluster increases autophagy protein expression, suggesting the canonical inverse relationship between Mirc1/Mir17-92 and autophagy gene expression. An in silico study for targets of Mirs that comprise the cluster suggested that the majority of the Mirs target autophagy mRNAs. Those targets were validated by luciferase assays. Notably, the ability of macrophages expressing mutant F508del CFTR to transport halide through their membranes is compromised and can be restored by downregulation of these inherently elevated Mirs, via restoration of autophagy. In vivo, downregulation of Mir17 and Mir20a partially restored autophagy expression and hence improved the clearance of Burkholderia cenocepacia. Thus, these data advance our understanding of mechanisms underlying the pathobiology of CF and provide a new therapeutic platform for restoring CFTR function and autophagy in patients with CF.

TGF-β-induced IL-6 prevents development of acute lung injury in influenza A virus-infected F508del CFTR-heterozygous mice

As the eighth leading cause of annual mortality in the USA, influenza A viruses are a major public health concern. In 20% of patients, severe influenza progresses to acute lung injury (ALI). However, pathophysiological mechanisms underlying ALI development are poorly defined. We reported that, unlike wild-type (WT) C57BL/6 controls, influenza A virus-infected mice that are heterozygous for the F508del mutation in the cystic fibrosis transmembrane conductance regulator (HETs) did not develop ALI. This effect was associated with higher IL-6 and alveolar macrophages (AMs) at 6 days postinfection (d.p.i.) in HET bronchoalveolar lavage fluid (BALF). In the present study, we found that HET AMs were an important source of IL-6 at 6 d.p.i. Infection also induced TGF-β production by HET but not WT mice at 2 d.p.i. TGF-β neutralization at 2 d.p.i. (TGF-N) significantly reduced BALF IL-6 in HETs at 6 d.p.i. Neither TGF-N nor IL-6 neutralization at 4 d.p.i. (IL-6-N) altered postinfection weight loss or viral replication in either mouse strain. However, both treatments increased influenza A virus-induced hypoxemia, pulmonary edema, and lung dysfunction in HETs to WT levels at 6 d.p.i. TGF-N and IL-6-N did not affect BALF AM and neutrophil numbers but attenuated the CXCL-1/keratinocyte chemokine response in both strains and reduced IFN-γ production in WT mice. Finally, bone marrow transfer experiments showed that HET stromal and myeloid cells are both required for protection from ALI in HETs. These findings indicate that TGF-β-dependent production of IL-6 by AMs later in infection prevents ALI development in influenza A virus-infected HET mice.

IFN-γ stimulates autophagy-mediated clearance of Burkholderia cenocepacia in human cystic fibrosis macrophages

Burkholderia cenocepacia is a virulent pathogen that causes significant morbidity and mortality in patients with cystic fibrosis (CF), survives intracellularly in macrophages, and uniquely causes systemic infections in CF. Autophagy is a physiologic process that involves engulfing non-functional organelles and proteins and delivering them for lysosomal degradation, but also plays a role in eliminating intracellular pathogens, including B. cenocepacia. Autophagy is defective in CF but can be stimulated in murine CF models leading to increased clearance of B. cenocepacia, but little is known about autophagy stimulation in human CF macrophages. IFN-γ activates macrophages and increases antigen presentation while also inducing autophagy in macrophages. We therefore, hypothesized that treatment with IFN-γ would increase autophagy and macrophage activation in patients with CF. Peripheral blood monocyte derived macrophages (MDMs) were obtained from CF and non-CF donors and subsequently infected with B. cenocepacia. Basal serum levels of IFN-γ were similar between CF and non-CF patients, however after B. cenocepacia infection there is deficient IFN-γ production in CF MDMs. IFN-γ treated CF MDMs demonstrate increased co-localization with the autophagy molecule p62, increased autophagosome formation, and increased trafficking to lysosomes compared to untreated CF MDMs. Electron microscopy confirmed IFN-γ promotes double membrane vacuole formation around bacteria in CF MDMs, while only single membrane vacuoles form in untreated CF cells. Bacterial burden is significantly reduced in autophagy stimulated CF MDMs, comparable to non-CF levels. IL-1β production is decreased in CF MDMs after IFN-γ treatment. Together, these results demonstrate that IFN-γ promotes autophagy-mediated clearance of B. cenocepacia in human CF macrophages.

Exaggerated inflammatory responses mediated by Burkholderia cenocepacia in human macrophages derived from Cystic fibrosis patients

Cystic fibrosis (CF) is accompanied with heightened inflammation worsened by drug resistant Burkholderia cenocepacia. Human CF macrophage responses to B. cenocepacia are poorly characterized and variable in the literature. Therefore, we examined human macrophage responses to the epidemic B. cenocepacia J2315 strain in order to identify novel anti-inflammatory targets. Peripheral blood monocyte derived macrophages were obtained from 23 CF and 27 non-CF donors. Macrophages were infected with B. cenocepacia J2315 and analyzed for cytokines, cytotoxicity, and microscopy. CF macrophages demonstrated significant increases in IL-1β, IL-10, MCP-1, and IFN-γ production in comparison to non-CF controls. CF patients on prednisone exhibited globally diminished cytokines compared to controls and other CF patients. CF macrophages also displayed increased bacterial burden and cell death. In conclusion, CF macrophages demonstrate exaggerated IL-1β, IL-10, MCP-1, and IFN-γ production and cell death during B. cenocepacia infection. Treatment with corticosteroids acutely suppressed cytokine responses.

Primary malignant melanoma of prostate

Primary genitourinary melanoma accounts for less than one per cent of all cases of melanoma. Most cases attributed to the prostate actually originate from the prostatic urethra. Due to its infrequency, primary malignant melanoma of the genitourinary tract presents a difficult diagnostic and management challenge. We report a case of primary malignant melanoma of the prostate found during transurethral resection of the prostate.

Transitional cell carcinoma of the ovary: a rare case and review of literature

Introduction

Transitional cell carcinoma (TCC) of the ovary is a rare, recently recognized, subtype of ovarian surface epithelial cancer.

Case presentation

A 69-year-old postmenopausal woman presented with a 2-year history of progressive enlargement of an abdominal mass. Abdominal computed tomography showed a pelvic mass. CA-125 was normal. A staging operation with total abdominal hysterectomy, bilateral salpingo-oophorectomy, infracolic omentectomy and pelvic lymph node dissection was performed. After surgery, the pathologic report of the right ovarian tumour was TCC, grade 3, stage IC. The patient underwent 3 cycles of chemotherapy: carboplatin and paclitaxel. She is regularly followed up and has been disease free for 10 months

Conclusion

Transitional cell carcinoma (TCC) of the ovary is a rare subtype of epithelial ovarian cancer. Surgical resection is the primary therapeutic approach, and patient outcomes after chemotherapy are better than for other types of ovarian cancers.

Chronic spontaneous nephrocutaneous fistula associated with renal replacement lipomatosis

Chronic spontaneous nephrocutaneous fistula is a rare renal disease. Renal replacement lipomatosis (RRL) is the result of the atrophy and destruction of renal parenchyma with massive increases in the amount of fat in the sinus and perirenal space. The 2 conditions can be associated because they may have the same etiology. Indeed, urolithiasis is the most common cause of these diseases. We report a case of chronic nephrocutaneous fistula associated with RRL due to both urolithiasis and renal tuberculosis.

Hypoxia induces chemoresistance in ovarian cancer cells by activation of signal transducer and activator of transcription 3

Signal transducer and activator of transcription 3 (STAT3) is activated in a variety of human cancers, including ovarian cancer. The molecular mechanism by which the STAT3 is activated in cancer cells is poorly understood. We observed that human ovarian xenograft tumors (A2780) in mice were severely hypoxic (pO(2) approximately 2 mmHg). We further observed that hypoxic exposure significantly increased the phosphorylation of STAT3 (pSTAT3) at the Tyr705 residue in A2780 cell line. The pSTAT3 (Tyr705) level was highly dependent on cellular oxygenation levels, with a significant increase at <2% O(2), and without any change in the pSTAT3 (Ser727) or total STAT3 levels. The pSTAT3 (Tyr705) elevation following hypoxic exposure could be reversed within 12 hr after returning the cells to normoxia. The increased level of pSTAT3 was partly mediated by increased levels of reactive oxygen species generation in the hypoxic cancer cells. Conventional chemotherapeutic drugs cisplatin and taxol were far less effective in eliminating the hypoxic ovarian cancer cells suggesting a role for pSTAT3 in cellular resistance to chemotherapy. Inhibition of STAT3 by AG490 followed by treatment with cisplatin or taxol resulted in a significant increase in apoptosis suggesting that hypoxia-induced STAT3 activation is responsible for chemoresistance. The results have important clinical implications for the treatment of hypoxic ovarian tumors using STAT3-specific inhibitors.