Tomasz Wandtke

Aptamers in Diagnostics and Treatment of Viral Infections

Aptamers are in vitro selected DNA or RNA molecules that are capable of binding a wide range of nucleic and non-nucleic acid molecules with high affinity and specificity. They have been conducted through the process known as SELEX (Systematic Evolution of Ligands by Exponential Enrichment). It serves to reach specificity and considerable affinity to target molecules, including those of viral origin, both proteins and nucleic acids. Properties of aptamers allow detecting virus infected cells or viruses themselves and make them competitive to monoclonal antibodies. Specific aptamers can be used to interfere in each stage of the viral replication cycle and also inhibit its penetration into cells. Many current studies have reported possible application of aptamers as a treatment or diagnostic tool in viral infections, e.g., HIV (Human Immunodeficiency Virus), HBV (Hepatitis B Virus), HCV (Hepatitis C Virus), SARS (Severe Acute Respiratory Syndrome), H5N1 avian influenza and recently spread Ebola. This review presents current developments of using aptamers in the diagnostics and treatment of viral diseases.

Challenges and Prospects for Alpha-1 Antitrypsin Deficiency Gene Therapy

Alpha-1 antitrypsin (AAT) is a protease inhibitor belonging to the serpin family. A number of identified mutations in the SERPINA1 gene encoding this protein result in alpha-1 antitrypsin deficiency (AATD). A decrease in AAT serum concentration or reduced biological activity causes considerable risk of chronic respiratory and liver disorders. As a monogenic disease, AATD appears to be an attractive target for gene therapy, particularly for patients with pulmonary dysfunction, where augmentation of functional AAT levels in plasma might slow down respiratory disease development. The short AAT coding sequence and its activity in the extracellular matrix would enable an increase in systemic serum AAT production by cellular secretion. In vitro and in vivo experimental AAT gene transfer with gamma-retroviral, lentiviral, adenoviral, and adeno-associated viral (AAV) vectors has resulted in enhanced AAT serum levels and a promising safety profile. Human clinical trials using intramuscular viral transfer with AAV1 and AAV2 vectors of the AAT gene demonstrated its safety, but did not achieve a protective level of AAT >11 μM in serum. This review provides an in-depth critical analysis of current progress in AATD gene therapy based on viral gene transfer. The factors affecting transgene expression levels, such as site of administration, dose and type of vector, and activity of the immune system, are discussed further as crucial variables for optimizing the clinical effectiveness of gene therapy in AATD subjects.

Enhanced expression of Fas Ligand (FasL) in the lower airways of patients with fibrotic interstitial lung diseases (ILDs).

The exact role of FasL, and particularly its soluble and membrane-bound forms, in the development of chronic ILDs and lung fibrosis has not been extensively explored. We aimed at analyzing membrane-bound FasL expression on alveolar macrophages (AM) and lymphocytes (AL) as well as soluble FasL (sFasL) levels in bronchoalveolar lavage (BAL) from ILDs patients, incl. pulmonary sarcoidosis (PS), hypersensitivity pneumonitis (HP), silicosis, asbestosis, idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), and healthy subjects (n = 89, 12, 7, 8, 23, 6, 17, respectively). In IPF, significantly increased percentage of AM FasL(+) and CD8(+)FasL(+) cells as well as sFasL levels in BAL were found. Increased sFasL levels were also observed in HP. NSIP and asbestosis were characterized by higher AM FasL(+) relative number; CD8(+)FasL(+) population was expanded in asbestosis only. There was a significant decline in AL FasL(+) percentage in PS and HP. Vital capacity was negatively correlated with sFasL levels, AM FasL(+) and CD8(+)FasL(+) cell relative count. CD4(+)FasL(+) and CD8(+)FasL(+) percentage strongly correlated with BAL neutrophilia, an unfavorable prognostic factor in lung fibrosis. The concurrent comparative BAL analysis of FasL expression indicates that FasL(+) AM and AL (mainly Tc cells) comprise an important element of the fibrotic process, mostly in IPF. FasL might play a crucial role in other fibrosis-complicated ILDs, like NSIP and asbestosis.

IL-27: A Key Player in Immune Regulation

Interleukin-27 plays an important role in the regulation of immune response. IL-27 signaling mediated by its heterodimeric IL-27Rα/gp130 receptor activates multiple signaling cascades, including STAT1 and STAT3, Akt/mTOR, ERK, and p38 MAPK pathways. Up- and downregulation of both receptor subunits and cross talk between immune cell populations regulate the magnitude of signal transduction. Transduction of IL-27 stimulatory signal is also limited through a reciprocal feedback loop involving SOCS3. Initial studies focused on proinflammatory activities of IL-27. IL-27 induces expression of T-bet and hence promotes Th1 cell differentiation and augments CD8+ T cell- and NK cell-mediated cytotoxicity. Simultaneously, IL-27 limits inflammation through its ability to negatively regulate GATA-3 and ROR-γt, key transcription factors of Th2 and Th17 cells, respectively. In contrast, Tr1 cell differentiation is positively stimulated by IL-27 through upregulation of c-Maf and Ahr further contributing to the limitation of the inflammation. Here, we have discussed the downstream signaling from the IL-27 receptor and its main molecular targets in immune cell subsets including Th1, Th2, Th17, Treg, Tr1, and Tfh cell population as well as B cells, DCs, and macrophages.

IL-27 in Health and Disease

Interleukin-27 plays an important role in the regulation of immune response. IL-27 activates multiple signaling cascades, including the JAK-STAT, Akt/mTOR, ERK, and p38 MAPK pathways. Multiple studies have revealed that IL-27 regulates Th1, Th2, Th17, Treg, Tr1, Tfh T cell population, as well as B cells, DCs, and macrophages. Due to its broad inhibitory effects, IL-27 is pivotal in maintenance of fetomaternal tolerance and prevention of autoimmunity. However, the same broad inhibitory capabilities seem to compromise immune response to bacterial pathogens. Here, we have discussed the role of IL-27 in bacterial, viral, and parasitic infections, chronic inflammation in asthma, COPD, psoriasis and inflammatory bowel disease and autoimmune disorders, such as systemic lupus erythematosus, rheumatoid arthritis, Sjogren’s syndrome, autoimmune uveitis, multiple sclerosis, and autoimmune thrombocytopenia. IL-27 represents also a novel, promising target/agent for the treatment of cancer; however, protumor activities have also been reported.

IL-27: Structure, Regulation, and Variability

Interleukin 27 (IL-27) is a novel cytokine secreted by stimulated antigen-presenting cells. Initial studies on the biology of IL-27 provided evidence for its role in the initiation of Th1 responses; however, subsequent work has indicated that IL-27 has broad stimulatory as well as inhibitory effects on Th1, Th2, Th17, Treg, and Tr1 subsets of T cells as well as NK cells and B cells. Together with other members of IL-12 family, it orchestrates initiation of inflammatory processes and sustains immune polarization. IL-27 is a heterodimer composed of IL-27p28 and EBI3. EBI3 has been found to form a biologically active complex with IL-12p35 (known as IL-35) and IL-23p19 (known as IL-39), while IL-27p28 can form a dimer with CLF. IL-27p28 has also its own inherent activity and can act on its own as IL-30. Here, we have discussed the variability of IL-27 gene, protein structure of IL-27 and its receptor, and molecular mechanisms regulating IL-27 expression.