Inhibition of Anti-HIV MicroRNA Expression: A Mechanism for Opioid-Mediated Enhancement of HIV Infection of Monocytes

TREX1 Knockdown Induces an Interferon Response to HIV that Delays Viral Infection in Humanized Mice.

Transcription factors of the interferon regulatory factor (IRF) family commands the entire type I interferon (IFN) system from induction of IFNs to diverse IFN responses, thereby providing a principal basis for host resistance against pathogens. However, the family has various additional roles. Regulating the development of the immune system, IRFs shape the establishment and execution of innate and adaptive immunity. IRFs also regulate growth and differentiation of many cell types, thus playing a role in leukemia and other cancers. In addition, evidence indicates that IRFs confer antiviral mechanisms not directly ascribed to the IFN system. This review deals with the diverse roles of IRFs in host defense and discusses the molecular mechanisms by which they regulate target gene transcription.

For many decades, cell-free nucleic acids have been known to be present in peripheral blood. Several studies have identified tumor-specific and/or tumor-associated alterations in the circulating nucleic acids of patients with various cancers. In recent years, cell-free microRNA (miRNA) have been stably detected in the plasma and serum, like other molecules; their presence in the blood has attracted the attention of researchers due to their potential use as valuable blood biomarkers.1Schwarzenbach H. Hoon D.S. Pantel K. Cell-free nucleic acids as biomarkers in cancer patients.Nat Rev Cancer. 2011; 11: 426-437Crossref PubMed Scopus (2199) Google Scholar MiRNAs are short, noncoding RNAs that play important roles in various physiologic and developmental processes. The mature miRNAs are produced from long primary transcripts through 2 sequential cleavage steps. The long primary miRNA transcript is cleaved by the Drosha complex in the nucleus, generating intermediate precursor miRNA. Precursor miRNA is transported by exportin-5 from the nucleus into the cytoplasm, and then subjected to further cleavage by a Dicer RNAase III enzyme, generating a short double-strand miRNA. One strand (guided strand) of mature miRNA is then incorporated into the RNA-induced silencing complex and subsequently hybridize to the 3′-untranslated region of their target mRNAs to repress translation or degrade these mRNAs. Thus, a single miRNA can influence the expression of hundreds of genes and allow them to function in a coordinated manner. Therefore, miRNAs have been implicated as key molecules in all cellular processes. Numerous studies have shown that alterations in miRNA expression correlate with various diseases, including the development and progression of cancer, and some miRNAs can function as oncogenes or tumor suppressors. These findings have opened up a new and interesting field in the diagnosis of cancer and the treatments of cancer patients. Mitchell et al2Mitchell P.S. Parkin R.K. Kroh E.M. et al.Circulating microRNAs as stable blood-based markers for cancer detection.Proc Natl Acad Sci U S A. 2008; 105: 10513-10518Crossref PubMed Scopus (6792) Google Scholar first demonstrated that circulating miRNAs had the potential to be new biomarkers in patients with solid cancers. In recent years, several papers have demonstrated that circulating miRNAs can also be detected in the peripheral blood of patients with digestive tract cancers. Although the origins and physiologic functions of cell-free miRNAs in the blood remain to be fully elucidated, a noninvasive assay for miRNAs should be developed to exploit these molecules as potential diagnostic and prognostic biomarkers. This assay undoubtedly contributes to an improvement in the clinical outcomes of cancer patients. In this article, we review the current state of biological and clinical research regarding circulating miRNAs of digestive tract cancer patients and discuss the future perspectives. It has been theorized that the necrosis and the apoptosis of tumor cells are the main sources of cell-free nucleic acids in the plasma and serum. However, several recent studies have demonstrated that extracellular nucleic acids, especially miRNAs, occur not only through cell lysis but also through active secretion.1Schwarzenbach H. Hoon D.S. Pantel K. Cell-free nucleic acids as biomarkers in cancer patients.Nat Rev Cancer. 2011; 11: 426-437Crossref PubMed Scopus (2199) Google Scholar, 3Valadi H. Ekström K. Bossios A. et al.Exosome-mediated transfer of mRNAs and microRNAs is a novel mechanism of genetic exchange between cells.Nat Cell Biol. 2007; 9: 654-659Crossref PubMed Scopus (9739) Google Scholar, 4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar, 5Pigati L. Yaddanapudi S.C. Iyengar R. et al.Selective release of microRNA species from normal and malignant mammary epithelial cells.PLoS One. 2010; 5: e13515Crossref PubMed Scopus (497) Google Scholar Cell-derived endogenous miRNAs are present in the blood in a remarkably stable form that is protected from endogenous RNase activity. In contrast, synthetic exogenous miRNAs are rapidly degraded when added directly to the plasma.2Mitchell P.S. Parkin R.K. Kroh E.M. et al.Circulating microRNAs as stable blood-based markers for cancer detection.Proc Natl Acad Sci U S A. 2008; 105: 10513-10518Crossref PubMed Scopus (6792) Google Scholar Kosaka et al4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar clearly demonstrated that a subset of miRNAs was packaged into exosome vesicles and released through a ceramide-dependent secretory mechanism. Arroyo et al6Arroyo J.D. Chevillet J.R. Kroh E.M. et al.Argonaute2 complexes carry a population of circulating microRNAs independent of vesicles in human plasma.Proc Natl Acad Sci U S A. 2011; 108: 5003-5008Crossref PubMed Scopus (2672) Google Scholar systematically investigated circulating miRNAs in the plasma and serum using differential centrifugation and size-exclusion chromatography techniques. This group demonstrated ≥2 populations of circulating miRNAs in the plasma and serum and discovered agonaute-2, a key effector protein involved in miRNA-mediated silencing as an miRNA carrier in the blood.6Arroyo J.D. Chevillet J.R. Kroh E.M. et al.Argonaute2 complexes carry a population of circulating microRNAs independent of vesicles in human plasma.Proc Natl Acad Sci U S A. 2011; 108: 5003-5008Crossref PubMed Scopus (2672) Google Scholar In addition, high-density lipoprotein has been described as an alternative transporter of extracellular miRNAs in human plasma.7Vickers K.C. Palmisano B.T. Shoucri B.M. et al.MicroRNAs are transported in plasma and delivered to recipient cells by high-density lipoproteins.Nat Cell Biol. 2011; 13: 423-433Crossref PubMed Scopus (2256) Google Scholar All circulating miRNAs, regardless of whether they are incorporated into protein complexes and/or cell-derived microvesicles, seem to be adequately protected against the degradation caused by the abundant RNases in human plasma and serum. Indeed, the extracellular miRNAs in the plasma and serum are extremely stable under severe conditions, such as extended storage and exposure to multiple freeze–thaw cycles.2Mitchell P.S. Parkin R.K. Kroh E.M. et al.Circulating microRNAs as stable blood-based markers for cancer detection.Proc Natl Acad Sci U S A. 2008; 105: 10513-10518Crossref PubMed Scopus (6792) Google Scholar Regarding the composition of circulating miRNAs, Pigati et al5Pigati L. Yaddanapudi S.C. Iyengar R. et al.Selective release of microRNA species from normal and malignant mammary epithelial cells.PLoS One. 2010; 5: e13515Crossref PubMed Scopus (497) Google Scholar investigated the difference between extracellular and cellular miRNAs using epithelial cell lines and concluded that the release of miRNAs did not necessarily reflect the abundance of miRNAs in the cell of origin. Kosaka et al4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar also demonstrated that some specific miRNAs were expressed to a greater extent in cell-derived exosomes compared with their donor cells.4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar Moreover, other groups demonstrated that the non–vesicle-associated miRNA profiles within protein complexes were distinctly different from the purified, exosomes-associated miRNA profiles.6Arroyo J.D. Chevillet J.R. Kroh E.M. et al.Argonaute2 complexes carry a population of circulating microRNAs independent of vesicles in human plasma.Proc Natl Acad Sci U S A. 2011; 108: 5003-5008Crossref PubMed Scopus (2672) Google Scholar These findings indicate that intracellular miRNAs are exported to the extracellular environment through a selective secretion mechanism. Interestingly, recent studies have demonstrated that extracellular miRNAs not only circulate in stable forms, but can also be incorporated into other surrounding and distant recipient cells in which they fulfill distinctive functions.8Skog J. Würdinger T. van Rijn S. et al.Glioblastoma microvesicles transport RNA and proteins that promote tumour growth and provide diagnostic biomarkers.Nat Cell Biol. 2008; 10: 1470-1476Crossref PubMed Scopus (3954) Google Scholar, 9Rechavi O. Erlich Y. Amram H. et al.Cell contact–dependent acquisition of cellular and viral nonautonomously encoded small RNAs.Genes Dev. 2009; 23: 1971-1979Crossref PubMed Scopus (100) Google Scholar, 10Zernecke A. Bidzhekov K. Noels H. et al.Delivery of microRNA-126 by apoptotic bodies induces CXCL12-dependent vascular protection.Sci Signal. 2009; 2: ra81Crossref PubMed Scopus (1130) Google Scholar, 11Kosaka N. Iguchi H. Ochiya T. Circulating microRNA in body fluid: a new potential biomarker for cancer diagnosis and prognosis.Cancer Sci. 2010; 101: 2087-2092Crossref PubMed Scopus (1144) Google Scholar, 12Pegtel D.M. Cosmopoulos K. Thorley–Lawson D.A. et al.Functional delivery of viral miRNAs via exosomes.Proc Natl Acad Sci U S A. 2010; 107: 6328-6333Crossref PubMed Scopus (1309) Google Scholar, 13Kosaka N. Iguchi H. Yoshioka Y. et al.Competitive Interactions of Cancer Cells and Normal Cells via Secretory MicroRNAs.J Biol Chem. 2012; 287: 1397-1405Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar Rechavi et al9Rechavi O. Erlich Y. Amram H. et al.Cell contact–dependent acquisition of cellular and viral nonautonomously encoded small RNAs.Genes Dev. 2009; 23: 1971-1979Crossref PubMed Scopus (100) Google Scholar demonstrated that functional signals spread across cell boundaries between immune cells in a contact-dependent manner. Pegtel et al12Pegtel D.M. Cosmopoulos K. Thorley–Lawson D.A. et al.Functional delivery of viral miRNAs via exosomes.Proc Natl Acad Sci U S A. 2010; 107: 6328-6333Crossref PubMed Scopus (1309) Google Scholar reported that Epstein–Barr virus miRNAs were secreted from infected B cells and were present in both the circulation and noninfected non-B cells. This group also demonstrated that miRNAs were transferred from infected to noninfected cells in vivo and were functional (upon transfer via exosomes) in primary monocyte-derived dendritic cells. Other groups have shown that miR-126 in apoptotic bodies derived from atherosclerotic endothelial cells induces the CXCL-12–dependent vascular protection process in recipient vascular cells.10Zernecke A. Bidzhekov K. Noels H. et al.Delivery of microRNA-126 by apoptotic bodies induces CXCL12-dependent vascular protection.Sci Signal. 2009; 2: ra81Crossref PubMed Scopus (1130) Google Scholar There have also been some reports regarding miRNA-mediated intercellular communication in a neoplastic environment. Skog et al8Skog J. Würdinger T. van Rijn S. et al.Glioblastoma microvesicles transport RNA and proteins that promote tumour growth and provide diagnostic biomarkers.Nat Cell Biol. 2008; 10: 1470-1476Crossref PubMed Scopus (3954) Google Scholar reported that microvesicles that housed miRNAs derived from glioblastomas were taken up by and fulfilled functions in human brain microvascular endothelial cells in culture. Kosaka et al4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar also demonstrated that miR-146a, which is a tumor-suppressive miRNA in prostate cancer, significantly knocked down the target ROCK1 protein expression and decreased cell proliferation in a recipient prostate cancer cell line.4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar Their subsequent paper demonstrated that a variety of tumor-suppressive miRNAs were secreted by a normal adult prostatic epithelial cell line, and among these secretory miRNAs, miR-143 could inhibit growth exclusively in cancer cells both in vitro and in vivo.13Kosaka N. Iguchi H. Yoshioka Y. et al.Competitive Interactions of Cancer Cells and Normal Cells via Secretory MicroRNAs.J Biol Chem. 2012; 287: 1397-1405Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar Other groups found that the let-7 miRNA family was abundant in the extracellular fractions derived from a metastatic gastric cancer (GC) cell line, but not those derived from a low metastatic parental cell line, and it has been speculated that some cancer cells maintain their oncogenesis via specific extracellular miRNAs.14Ohshima K. Inoue K. Fujiwara A. et al.Let-7 microRNA family is selectively secreted into the extracellular environment via exosomes in a metastatic gastric cancer cell line.PLoS One. 2010; 5: e13247Crossref PubMed Scopus (515) Google Scholar On the other hand, exosomes released from neoplastic cells have been reported to suppress immune surveillance, and cell-free miRNAs contained within the exosomes may be responsible for the immunosuppression systems.15Zhang H.G. Grizzle W.E. Exosomes and cancer: a newly described pathway of immune suppression.Clin Cancer Res. 2011; 17: 959-964Crossref PubMed Scopus (233) Google Scholar These findings support the presence of miRNA-mediated intercellular communication in the normal cellular environment and the tumor environment (Figure 1) . Several methods can be used for extracting miRNAs; however, efficient protocols with high reproducibility should be utilized for the extraction of circulating miRNAs owing to the small amounts present in the plasma and serum. Commercial extraction kits that utilize glass fiber filters in the purification process have been widely used for clinical blood samples, and there are several methods for quantification. A polymerase chain reaction (PCR)-based technique using a stem-loop reverse-transcriptase (RT) primer has been widely used for determining quantity. A microarray assay, which can analyze hundreds of miRNAs simultaneously, has also been utilized for the identification of a specific marker among many circulating miRNAs. Recent advances in technology allow for the use of an oligonucleotide array to quantify the amount of circulating miRNAs without the need for PCR. Most recently, researchers have identified circulating miRNAs as new diagnostic markers in patients with cancer using direct sequencing methods16Brase J.C. Wuttig D. Kuner R. et al.Serum microRNAs as non–invasive biomarkers for cancer.Mol Cancer. 2010; 9: 306Crossref PubMed Scopus (366) Google Scholar (Table 117Zhang C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google Scholar, 18Komatsu S. Ichikawa D. Takeshita H. et al.Circulating microRNAs in plasma of patients with oesophageal squamous cell carcinoma.Br J Cancer. 2011; 105: 104-111Crossref PubMed Scopus (233) Google Scholar, 19Tsujiura M. Ichikawa D. Komatsu S. et al.Circulating microRNAs in plasma of patients with gastric cancers.Br J Cancer. 2010; 102: 1174-1179Crossref PubMed Scopus (578) Google Scholar, 20Liu R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google Scholar, 21Liu H. Zhu L. Liu B. et al.Genome-wide microRNA profiles identify miR-–378 as a serum biomarker for early detection of gastric cancer.Cancer Lett. 2012; 316: 196-203Crossref PubMed Scopus (234) Google Scholar, 22Konishi H. Ichikawa D. 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Zhang L. et al.Circulating plasma is a novel biomarker for metastatic cancer and One. 2011; PubMed Scopus Google Scholar, Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google Scholar, Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Scholar, Zhang K. H. et al.Circulating microRNAs as biomarkers for 2011; PubMed Scopus Google Scholar, Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google Scholar, J. C. X. et al.Circulating and in patients with or 2011; PubMed Scopus Google Scholar, J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Scholar, Y. H. H. et al.Circulating as a novel biomarker for 2012; 56: Full Text Full Text PDF PubMed Scopus Google Scholar, J. Y. X. et al.Serum microRNA as a potential marker for Sci. 2011; PubMed Scopus Google Scholar, J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google Scholar, A. N. et and and in with circulating and Res. 2010; PubMed Scopus Google Scholar, Huang X. H. et al.Circulating as a novel marker in 2010; PubMed Scopus Google Scholar, S. K. Chen et expressed miRNAs in the plasma may provide a signature for J Res. 2010; Google Scholar, N. A. et and serum microRNAs in the and in patients with One. 2011; PubMed Scopus Google Scholar, R. Komatsu S. Ichikawa D. et diagnostic of circulating in plasma of patients with J Cancer. 2011; 105: PubMed Scopus Google Scholar, J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google miRNAs in cell or other C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google S. Ichikawa D. Takeshita H. et al.Circulating microRNAs in plasma of patients with oesophageal squamous cell carcinoma.Br J Cancer. 2011; 105: 104-111Crossref PubMed Scopus (233) Google M. Ichikawa D. Komatsu S. et al.Circulating microRNAs in plasma of patients with gastric cancers.Br J Cancer. 2010; 102: 1174-1179Crossref PubMed Scopus (578) Google or other R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google in the H. Zhu L. Liu B. et al.Genome-wide microRNA profiles identify miR-–378 as a serum biomarker for early detection of gastric cancer.Cancer Lett. 2012; 316: 196-203Crossref PubMed Scopus (234) Google H. Ichikawa D. Komatsu S. et al.Detection of gastric cancer–associated microRNAs on microRNA microarray comparing pre- and post-operative plasma.Br J Cancer. 2012; 106: 740-747Crossref PubMed Scopus (165) Google E.K. Chong W.W. Jin H. et al.Differential expression of microRNAs in plasma of patients with colorectal cancer: a potential marker for colorectal cancer screening.Gut. 2009; 58: 1375-1381Crossref PubMed Scopus (1055) Google Z. Huang D. Ni S. et al.Plasma microRNAs are promising novel biomarkers for early detection of colorectal cancer.Int J Cancer. 2010; 127: 118-126Crossref PubMed Scopus (868) Google in the L.G. Gu J. Serum is a promising novel marker for early detection of colorectal 2012; PubMed Scopus Google cancer H. Zhang L. et al.Circulating plasma is a novel biomarker for metastatic cancer and One. 2011; PubMed Scopus Google in the Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google in the Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Zhang K. H. et al.Circulating microRNAs as biomarkers for 2011; PubMed Scopus Google Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google not for J. C. X. et al.Circulating and in patients with or 2011; PubMed Scopus Google in the J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Y. H. H. et al.Circulating as a novel biomarker for 2012; 56: Full Text Full Text PDF PubMed Scopus Google J. Y. X. et al.Serum microRNA as a potential marker for Sci. 2011; PubMed Scopus Google in the J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google A. N. et and and in with circulating and Res. 2010; PubMed Scopus Google in the Huang X. H. et al.Circulating as a novel marker in 2010; PubMed Scopus Google S. K. Chen et expressed miRNAs in the plasma may provide a signature for J Res. 2010; Google N. A. et and serum microRNAs in the and in patients with One. 2011; PubMed Scopus Google R. Komatsu S. Ichikawa D. et diagnostic of circulating in plasma of patients with J Cancer. 2011; 105: PubMed Scopus Google in the J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google microRNA colorectal direct esophageal gastric polymerase chain in the in a new microRNA colorectal direct esophageal gastric polymerase chain Zhang et C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google Scholar have investigated the serum miRNA profiles of patients with esophageal squamous cell using miRNAs using direct this group identified serum miRNAs and as biomarkers. The under the for the miRNAs were for serum tumor and patients in the early of the could be from using the miRNA C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google Scholar plasma from group also the plasma expression of miRNAs that were to be with the development of on found that the plasma of to be in patients in the and the were significantly in compared with A of the in plasma was the of an in serum tumor which that circulating miRNAs may be for diagnosis of in S. Ichikawa D. Takeshita H. et al.Circulating microRNAs in plasma of patients with oesophageal squamous cell carcinoma.Br J Cancer. 2011; 105: 104-111Crossref PubMed Scopus (233) Google Scholar However, there have been reports regarding circulating miRNAs for the other group first reported the of circulating miRNAs as biomarkers in patients with miRNAs and which have been reported to be in as miRNAs and their in plasma using In the plasma of these miRNAs the tumor miRNA and were significantly in patients in the also found that the plasma of these miRNAs were significantly in compared with M. Ichikawa D. Komatsu S. et al.Circulating microRNAs in plasma of patients with gastric cancers.Br J Cancer. 2010; 102: 1174-1179Crossref PubMed Scopus (578) Google Scholar Liu et R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google Scholar have investigated the serum miRNA profiles of patients with using miRNAs using direct this group identified serum miRNAs and as biomarkers for found that the expression of serum miRNAs was with the tumor and the for the miRNAs were for serum tumor R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google Scholar Other groups have investigated serum miRNA profiles using miRNA and concluded that was the biomarker for detection in the serum, with and the expression in primary was compared with normal H. Zhu L. Liu B. et al.Genome-wide microRNA profiles identify miR-–378 as a serum biomarker for early detection of gastric cancer.Cancer Lett. 2012; 316: 196-203Crossref PubMed Scopus (234) Google Scholar The selective release of specific cellular miRNAs from the tumor cells or from normal as could these et E.K. Chong W.W. Jin H. et al.Differential expression of microRNAs in plasma of patients with colorectal cancer: a potential marker for colorectal cancer screening.Gut. 2009; 58: 1375-1381Crossref PubMed Scopus (1055) Google Scholar first reported that circulating miRNAs could be potential noninvasive markers for colorectal cancer patients. This group plasma from patients using a miRNA microarray and found that and were in the plasma of patients and in compared with they demonstrated that the detection of could from other and The was with and an E.K. Chong W.W. 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Serum is a promising novel marker for early detection of colorectal 2012; PubMed Scopus Google Scholar the serum expression of miRNAs and in and metastatic patients and reported that serum had the potential to be a noninvasive biomarker for the early detection of in L.G. Gu J. Serum is a promising novel marker for early detection of colorectal 2012; PubMed Scopus Google Scholar et Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google Scholar reported the first of the direct of circulating miRNAs from the plasma without RNA extraction and found that the direct of plasma could be used as a potential noninvasive diagnostic and prognostic biomarker for Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google Scholar et Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Scholar first reported the of circulating miRNAs as biomarker for cancer identified as an miRNA of by miRNA profiles in the process of development using of serum was found in the of of patients and the were significantly Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Scholar et Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google Scholar investigated the serum of miRNAs and to identify new but only the was significantly in the serum of patients compared with or viral B patients without and the of were also significantly in serum Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google Scholar et J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Scholar investigated plasma miRNAs using an miRNA microarray in a of patients. This group first on the of the microarray and subsequently identified miRNAs and using for the miRNA reported that their miRNA could patients from B patients and patients and it is a promising marker for the early diagnosis of J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Scholar Wang et J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google Scholar the plasma of miRNAs and that have been implicated in cancer development in The plasma of miRNA were in patients compared with the The for miRNA were not but they to when the miRNAs were J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google Scholar et A. N. et and and in with circulating and Res. 2010; PubMed Scopus Google Scholar identified 2 of the family and that were in using This group also found that these 2 miRNAs were significantly in the of and patients compared with of and et N. A. et and serum microRNAs in the and in patients with One. 2011; PubMed Scopus Google Scholar identified serum miRNAs and as diagnostic biomarkers of in an circulating miRNAs and demonstrated that the circulating miRNAs could as not only diagnostic markers but also of the Liu et J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google Scholar miRNA and in the plasma of and patients using All miRNA were significantly in patients compared with patients and This group concluded that the of and the marker was among various in from and J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google Scholar Circulating miRNAs are for use as valuable biomarkers owing to their in the and of Therefore, circulating miRNAs may be used for the clinical in cancer and early or and for the the small of which is a that miRNAs from other for an of using and direct

There is accumulating evidence that the p38 MAP kinase pathway plays important roles in Type I interferon (IFN) signaling, but the mechanisms regulating p38 activation during engagement of the Type I IFN receptor remain to be defined. We sought to identify the events that lead to activation of the p38 MAP kinase in response to Type I IFNs. Our data demonstrate that treatment of sensitive cell lines with IFNalpha results in activation of both MAP kinase kinase 3 (MKK3) and MAP kinase kinase 6 (MKK6). Such IFN-inducible activation of MKK3 and MKK6 is essential for downstream phosphorylation and activation of the p38 MAP kinase, as shown by studies using mouse embryonic fibroblasts (MEFs) with targeted disruption of the Mkk3 and Mkk6 genes (MKK3-/- MKK6-/-). Similarly, IFN-dependent activation of the downstream effectors of p38, MAPKAPK-2 and MAPKAPK-3, is not detectable in cells lacking Mkk3 and Mkk6, demonstrating that the function of these MAP kinase kinases is required for full activation of the p38 pathway. To define the functional relevance of MKK3/6 engagement in Type I IFN signaling, IFN-inducible gene transcription was evaluated in the MKK3/MKK6 double knock-out cells. IFNalpha- and IFNbeta-dependent transcription via either interferon-stimulated response element or IFNgamma activated site elements was defective in MKK3 -/-/MKK6 -/- MEFs in luciferase reporter assays. In addition, IFN-dependent induction of two genes known to be of importance in the generation of IFN responses, Isg15 and Irf-9, was diminished in the absence of Mkk3 and Mkk6. The effects of Mkk3 and Mkk6 on IFN-dependent transcription were unrelated to any effects on the phosphorylation and activation of STAT proteins, indicating the presence of a STAT-independent mechanism. Altogether, our findings demonstrate that MKK3 and MKK6 are rapidly activated during engagement of the Type I IFN receptor and play important roles in Type I IFN signaling and the generation of IFN responses.

Detection of foreign RNA by the innate immune system can trigger the induction of type I interferon (IFN) and apoptosis. Important antiviral defense pathways that result in type I IFN production following the recognition of foreign double-stranded RNA (dsRNA) include the RIG-I family helicases and IPS-1 adaptor cytosolic pathway and the Toll-like receptor 3 and TIR domain-containing adaptor-inducing IFN-beta (TRIF) adaptor membrane-associated pathway, both of which activate IFN regulatory factor 3 (IRF3). In addition to triggering an innate immune response, dsRNAs are widely used to mediate gene-selective silencing in mammalian cells by the RNA interference pathway. We investigated the ability of short interfering RNAs, including T7 phage polymerase-synthesized RNA (PRNA), which like some viral RNAs contains a 5'-triphosphate, to selectively silence gene expression and to cause induction of IFN-beta and apoptosis. We found that PRNA-mediated gene silencing and associated nonspecific pro-apoptotic and IFN-inducing effects were dependent on the cell line and RNA length. Double-stranded PRNAs 50 nucleotides long as well as polyinosinic-polycytidylic acid activated the RNA-dependent protein kinase (PKR) and induced significant levels of IFN-beta and apoptosis, whereas shorter PRNAs and chemically synthesized dsRNAs did not. Effector caspase activation and apoptosis following RNA transfection was enhanced by pretreatment with IFN, and removal of the 5'-phosphate from PRNAs decreased induction of both IFN-beta and apoptosis. PKR, in addition to IPS-1 and IRF3 but not TRIF, was required for maximal type I IFN-beta induction and the induction of apoptosis by both transfected PRNAs and polyinosinic-polycytidylic acid.

Moloney leukemia virus 10 (MOV10) protein is a superfamily-1 RNA helicase, and it is also a component of the RNA-induced silencing complex. Recent studies have shown that MOV10 plays an active role in the RNA interference pathway. Here, we report that MOV10 inhibits retrovirus replication. When it was overexpressed in viral producer cells, MOV10 was able to reduce the infectivity of human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus, and murine leukemia virus. Conversely, when MOV10 expression was reduced by small interfering RNAs, HIV-1 infectivity was increased. Consistently, silencing of MOV10 expression in a human T cell line enhanced HIV-1 replication. Furthermore, we found that MOV10 interacts with HIV-1 nucleocapsid protein in an RNA-dependent manner and is packaged into virions. It blocks HIV-1 replication at a postentry step. In addition, we also found that HIV-1 could suppress MOV10 protein expression to counteract this cellular resistance. All of these results indicate that MOV10 has a broad antiretroviral activity that can target a wide range of retroviruses, and it could be actively involved in host defense against retroviral infection.

Epidemic of Lung Cancer in Patients With HIV Infection

Over the last decade, small noncoding RNA molecules such as microRNAs (miRNAs) have emerged as critical regulators in the expression and function of eukaryotic genomes. It has been suggested that viral infections and neurological disease outcome may also be shaped by the influence of small RNAs. This has prompted us to suggest that HIV infection alters the endogenous miRNA expression patterns, thereby contributing to neuronal deregulation and AIDS dementia. Therefore, using primary cultures and neuronal cell lines, we examined the impact of a viral protein (HIV-1 Tat) on the expression of miRNAs due to its characteristic features such as release from the infected cells and taken up by noninfected cells. Using microRNA array assay, we demonstrated that Tat deregulates the levels of several miRNAs. Interestingly, miR-34a was among the most highly induced miRNAs in Tat-treated neurons. Tat also decreases the levels of miR-34a target genes such as CREB protein as shown by real time PCR. The effect of Tat was neutralized in the presence of anti-miR-34a. Using in situ hybridization assay, we found that the levels of miR-34a increase in Tat transgenic mice when compared with the parental mice. Therefore, we conclude that deregulation of neuronal functions by HIV-1 Tat protein is miRNA-dependent.

Pulmonary Hypertension: From an Orphan Disease to a Public Health Problem

The human immunodeficiency virus type-1 (HIV-1) infects microglia, macrophages, and astrocytes in the central nervous system (CNS) and may cause severe neurological diseases, such as AIDS-related dementias or progressive encephalopathies, as a result of CNS inflammation and neurotrophin signaling defects associated with expression of viral antigens and HIV-1 replication in the brain. The HIV Tat protein can be endocytosed by surrounding uninfected cells; interacts with transcriptional coactivators/acetyltransferases, p300/CREB-binding protein, and p300/CREB-binding protein-associated factor (PCAF); and induces neuronal apoptosis. Since nerve growth factor (NGF) receptor and brain-derived neurotrophic factor receptor signaling through CREB requires p300 and PCAF histone acetyltransferases, we sought to determine whether HIV-1 Tat coactivator interactions interfere with neurotrophin receptor signaling in neuronal cells. Here, we demonstrate that Tat-coactivator interactions inhibit NGF- and brain-derived neurotrophic factor-responsive CRE trans-activation and neurotrophin protection against apoptosis in PC12 and IMR-32 neuroblastoma cells. Purified recombinant Tat or Tat-derived synthetic peptides, spanning p300- and PCAF-binding sequences, inhibit histone H3/H4 acetylation in vitro. A Tat mutant, TatK28A/K50A, defective for binding p300 and PCAF, neither repressed NGF-responsive CRE transactivation nor inhibited histone acetylation. HIV-1 Tat interacts in PCAF complexes in post-mortem CNS tissues from donor neuro-AIDS patients, as determined by fluorescence resonance energy transfer immunoconfocal microscopy. Importantly, these findings suggest that HIV-1 Tat-coactivator interactions may contribute to neurotrophin signaling impairments and neuronal apoptosis associated with HIV-1 infections of the CNS.

Expression of Long Anti-HIV-1 Hairpin RNAs for the Generation of Multiple siRNAs: Advantages and Limitations

Viruses and hosts have coevolved for millions of years, leading to the development of complex host–pathogen interactions. Influenza A virus (IAV) causes severe pulmonary pathology and is a recurrent threat to human health. Innate immune sensing of IAV triggers a complex chain of host responses. IAV has adapted to evade host defense mechanisms, and the host has coevolved to counteract these evasion strategies. However, the molecular mechanisms governing the balance between host defense and viral immune evasion is poorly understood. Here, we show that the host protein DEAD-box helicase 3 X-linked (DDX3X) is critical to orchestrate a multifaceted antiviral innate response during IAV infection, coordinating the activation of the nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 (NLRP3) inflammasome, assembly of stress granules, and type I interferon (IFN) responses. DDX3X activated the NLRP3 inflammasome in response to WT IAV, which carries the immune evasive nonstructural protein 1 (NS1). However, in the absence of NS1, DDX3X promoted the formation of stress granules that facilitated efficient activation of type I IFN signaling. Moreover, induction of DDX3X-containing stress granules by external stimuli after IAV infection led to increased type I IFN signaling, suggesting that NS1 actively inhibits stress granule–mediated host responses and DDX3X-mediated NLRP3 activation counteracts this action. Furthermore, the loss of DDX3X expression in myeloid cells caused severe pulmonary pathogenesis and morbidity in IAV-infected mice. Together, our findings show that DDX3X orchestrates alternate modes of innate host defense which are critical to fight against NS1-mediated immune evasion strategies during IAV infection.

MicroRNAs and the Regulation of Vector Tropism

COVID-19 vasculitis and novel vasculitis mimics.

A Critical Role for Type I IFN–dependent NK Cell Activation in Innate Immune Elimination of Adenoviral Vectors In Vivo