Epigenetics and chromatin remodeling play a role in lung disease

Epigenetics is defined as heritable changes that affect gene expression without altering the DNA sequence. Epigenetic regulation of gene expression is facilitated through different mechanisms such as DNA methylation, histone modifications and RNA-associated silencing by small non-coding RNAs. All these mechanisms are crucial for normal development, differentiation and tissue-specific gene expression. These three systems interact and stabilize one another and can initiate and sustain epigenetic silencing, thus determining heritable changes in gene expression. Histone acetylation regulates diverse cellular functions including inflammatory gene expression, DNA repair and cell proliferation. Transcriptional coactivators possess intrinsic histone acetyltransferase activity and this activity drives inflammatory gene expression. Eleven classical histone deacetylases (HDACs) act to regulate the expression of distinct subsets of inflammatory/immune genes. Thus, loss of HDAC activity or the presence of HDAC inhibitors can further enhance inflammatory gene expression by producing a gene-specific change in HAT activity. For example, HDAC2 expression and activity are reduced in lung macrophages, biopsy specimens, and blood cells from patients with severe asthma and smoking asthmatics, as well as in patients with chronic obstructive pulmonary disease (COPD). This may account, at least in part, for the enhanced inflammation and reduced steroid responsiveness seen in these patients. Other proteins, particularly transcription factors, are also acetylated and are targets for deacetylation by HDACs and sirtuins, a related family of 7 predominantly protein deacetylases. Thus the acetylation/deacetylation status of NF-κB and the glucocorticoid receptor can also affect the overall expression pattern of inflammatory genes and regulate the inflammatory response. Understanding and targeting specific enzymes involved in this process might lead to new therapeutic agents, particularly in situations in which current anti-inflammatory therapies are suboptimal

Exosomes and Exosomal miRNA in Respiratory Diseases

Exosomes are nanosized vesicles released from every cell in the body including those in the respiratory tract and lungs. They are found in most body fluids and contain a number of different biomolecules including proteins, lipids, and both mRNA and noncoding RNAs. Since they can release their contents, particularly miRNAs, to both neighboring and distal cells, they are considered important in cell-cell communication. Recent evidence has shown their possible importance in the pathogenesis of several pulmonary diseases. The differential expression of exosomes and of exosomal miRNAs in disease has driven their promise as biomarkers of disease enabling noninvasive clinical diagnosis in addition to their use as therapeutic tools. In this review, we summarize recent advances in this area as applicable to pulmonary diseases

Association between vitamin d deficiencies in sarcoidosis with disease activity, course of disease and stages of lung involvements

Background: Despite negative association between 25-hydroxy vitamin D and incidence of many chronic respiratory diseases, this feature was not well studied in sarcoidosis. Current study investigated the association between 25-hydroxy vitamin D deficiency with sarcoidosis chronicity, disease activity, extra-pulmonary skin manifestations, urine calcium level and pulmonary function status in Iranian sarcoidosis patients. Results of this study along with future studies, will supply more effective programs for sarcoidosis treatment. Methods: Eighty sarcoidosis patients in two groups of insufficient serum level and sufficient serum level of 25-hydroxy vitamin D were studied. Course of sarcoidosis was defined as acute and chronic sarcoidosis. Pulmonary function test (PFT) was assessed by spirometry. Skin involvements were defined as biopsy proven skin sarcoidosis. 24-hour urine calcium level was used to specify the disease activity. Stages of lung involvements were obtained by CT-scan and chest X-ray. The statistical analyses were evaluated using Statistical Package for the Social Sciences. Results: A significant negative correlation was obtained between vitamin D deficiency in sarcoidosis patients and disease chronic course and stages two to four of lung involvements. Considering other parameters of the disease and vitamin D deficiency, no significant correlation was detected. Conclusions: In conclusion, results of the current study implies in the role of vitamin 25(OH)D deficiencies in predicting the course of chronic sarcoidosis. Furthermore, it was concluded that vitamin 25(OH)D deficiency can direct pulmonary sarcoidosis toward stage 2–4 of lung involvements

Reduced Phagocytic Capacity of Blood Monocyte/Macrophages in Tuberculosis Patients Is Further Reduced by Smoking.

Tuberculosis (TB) and tobacco use are two major alarming global health issues posing immense threats to human populations. Mycobacterium tuberculosis (MTB) by activation of macrophages could induce the sequences of cells activation and releases of inflammatory cytokines such as CXCL-8, Il-12 and TNF-α which in turn induces the immune system network. However no information is available on other activity of cells by MTB and smoking. In the current study we aimed to investigate the serum levels TNF-a, CXCL-8 and phagocytosis capacity in tuberculosis patients with and without smoking. 103 subjects entered the study including 61 new diagnosed pulmonary TB patients (23 smokers and 38 nonsmokers) and 42 control healthy subjects. The phagocytosis of fluorescein isothiocyanate dextran (FITC-dextran) in blood monocytes/macrophages through flowcytometry was assessed. Serum levels of TNF-a and CXCL-8 were analyzed by ELISA methods. A lower percentage of cells from TB patients who smoked [50.29% (43.4-57.2), p<0.01] took up FITC-dextran after 2h compared to non-smoking TB subjects [71.62% (69.2-74.1)] and healthy cases [97.45% (95.9-99.1). Phagocytic capacity was inversely correlated with cigarette smoking as measured by pack years (r=-0.73, p<0.001). The serum levels of TNF-a and CXCL-8 were significantly higher in the TB patients who smoked compared to the TB non-smoker group (p<0.001, p<0.01 respectively). Blood monocytes/macrophages from TB patients have reduced phagocytic capacity which is further reduced in TB patients who smoke. Smoking enhanced serum levels of TNF-a and CXCL-8 suggesting a greater imbalance between the proinflammatory and anti-inflammatory factors in these patients

Circulating levels of monocytic myeloid-derived suppressor cells (M-MDSC) and CXCL-8 in non-small cell lung cancer (NSCLC)

BACKGROUND: Myeloid-derived suppressor cells (MDSC) are categorized as granulocytic (G-MDSCs) and monocytic (M-MDSCs) and their expansion play a role in cancer progression. Recruitment to the cancer site depends upon the presence of a chemoattractant. We aimed to investigate the presence of MDSC subtypes and of interleukin-8 (CXCL-8) in the peripheral blood in lung cancer subtypes including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) patients. MATERIALS AND METHODS: Peripheral blood samples of 26 NSCLC patients, 18 SCLC patients, and 8 healthy control donors (HDs) were harvested and the surface expression of CD14, CD15, CD11b, and HLA-DR on MDSCs was measured using flow cytometry. The level of serum CXCL8 was measured by the ELISA method. RESULTS: The frequency of circulating M-MDSCs was significantly higher in patients with NSCLC than in SCLC and HDs. In contrast, there was no statistical difference concerning the frequency of circulating G-MDSCs between the three groups. The concentration of CXCL-8 was significantly higher in the NSCLC and SCLC patients than in HD control with no significant difference between NSCLC and SCLC groups. There was no correlation between serum CXCL8 and G-MDSC levels. CONCLUSION: Our data confirm a higher frequency of circulating M-MDSCs, but not G-MDSCs, in the blood of those suffering from NSCLC but not for SCLC cases. Measuring MDSC subtypes and serum chemotactic factors may have implications for the differential diagnosis of NSCLC

What Immunological Defects Predispose to Non-tuberculosis Mycobacterial Infections?

Nontuberculous mycobacteria (NTM) are categorized as one of the large and diverse groups of environmental organisms which are abundant in water and soil.  NTM cause a variety of diseases in humans that mainly affect the lung. A predisposition to pulmonary NTM is evident in patients with parenchymal structural diseases including bronchiectasis, emphysema, tuberculosis (TB), cystic fibrosis (CF), rheumatologic lung diseases and other chronic diseases with pulmonary manifestations. Lung infections are not the only consequences of being infected by NTM as they can also infect skin and soft tissue and may also cause lymphadenitis (predominantly in young children) and disseminated disease in human immunodeficiency virus (HIV)-infected patients or those with severely compromised immune system. NTM are also found in many subjects without any known risk factors.  Although the recent advances in imaging and microbiologic techniques including gene sequencing have provided a better view of the problems caused by NTM and has enhanced our understanding of the disease, many uncertainties regarding the immunologic response to NTM still exist. There is also limited data on the immunogenetics of NTM infection. Here, the authors reviewed the main immunogenetic defects as well as other immunological conditions which are associated with an increased the risk of NTM infections

The prevalence of cryptococcal antigenemia in serum of human immunodeficiency viruses-infected patients of iran

BACKGROUND: Cryptococcus species are the most prevalent opportunistic agents found in patients with HIV which may result in life-threatening cryptococcal meningitis (CM). A non-invasive way for diagnosis of CM is the detection of cryptococcal antigen (CrAg) in the blood to reduce either the mortality rate or the treatment complications associated with antiretroviral therapy. Not much information is available in CM among HIV patients in Iran. AIM: Thus, in the current study, we aimed to evaluate the prevalence of cryptococcal disease by antigen testing, possible associated factors, and outcomes in HIV-infected patients being managed in a referral HIV/TB hospital in Tehran-Iran. METHODS: In this cross-sectional study, blood samples were screened for CrAg using a rapid latex agglutination test between 2017 and 2018 at Masih Daneshvari Hospital (Tehran-Iran) as referral land center for HIV/TB patients. Based on CD4 counts, 106 HIV-positive infected patients including 101 (95.3) males and 5 (4.7) females with the mean ± standard deviation age of 42.40 ± 10.687 and 36.50 ± 6.403 years enrolled in the study. The patients were categorized into 4 groups, (a) &lt;50, (b) 50�100, (c) 101�200, and (d)&gt;200 CD4+ T cells/µL. Whole blood was obtained with EDTA (for flow cytometry of CD4 counts) or without for harvesting serum for determination of CrAg in serum. RESULTS: The results showed only one positive case for CrAg, indicating that CrAg is rare in Iranian HIV patients (overall estimation is lower than 0.01). CONCLUSIONS: With the paucity of information about the prevalence of cryptococcosis in Iran, there is a need for better screening tests and strategies for detection of CrAg in addition to the prevention and treatment approaches of CM. © 2020 Monireh Kamali, Payam Tabarsi, Khorshid Badihi, Esmaeil Mortaz

Effects of the polyunsaturated fatty acids, EPA and DHA, on hematological malignancies: a systematic review

Omega-3 polyunsaturated fatty acids (PUFAs) have well established anti-cancer properties. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are among this biologically active family of macromolecules for which various anti-cancer effects have been explained. These PUFAs have a high safety profile and can induce apoptosis and inhibit growth of cancer cells bothin vitroandin vivo, following a partially selective manner. They also increase the efficacy of chemotherapeutic agents by increasing the sensitivity of different cell lines to specific anti-neoplastic drugs. Various mechanisms have been proposed for the anti-cancer effects of these omega-3 PUFAs; however, the exact mechanisms still remain unknown. While numerous studies have investigated the effects of DHA and EPA on solid tumors and the responsible mechanisms, there is no consensus regarding the effects and mechanisms of action of these two FAs in hematological malignancies. Here, we performed a systematic review of the beneficial effects of EPA and DHA on hematological cell lines as well as the findings of relatedin vivostudies and clinical trials. We summarize the key underlying mechanisms and the therapeutic potential of these PUFAs in the treatment of hematological cancers. Differential expression of apoptosis-regulating genes and Glutathione peroxidase 4 (Gp-x4), varying abilities of different cancerous and healthy cells to metabolize EPA into its more active metabolites and to uptake PUFAS are among the major factors that determine the sensitivity of cells to DHA and EPA. Considering the abundance of data on the safety of these FAs and their proven anti-cancer effects in hematological cell lines and the lack of related human studies, further research is warranted to find ways of exploiting the anticancer effects of DHA and EPA in clinical settings both in isolation and in combination with other therapeutic regimens