A novel nonsteroidal antifibrotic oligo decoy containing the TGF-beta element found in the COL1A1 gene which regulates murine schistosomiasis liver fibrosis

The role of microRNAs in the pathogenesis, grading and treatment of hepatic fibrosis in schistosomiasis

Schistosomiasis is a prevalent parasitic disease worldwide. The main pathological changes of hepatosplenic schistosomiasis are hepatic granuloma and fibrosis due to worm eggs. Portal hypertension and ascites induced by hepatic fibrosis are usually the main causes of death in patients with chronic hepatosplenic schistosomiasis. Currently, no effective vaccine exists for preventing schistosome infections. For quite a long time, praziquantel (PZQ) was widely used for the treatment of schistosomiasis and has shown benefit in treating liver fibrosis. However, drug resistance and chemical toxicity from PZQ are being increasingly reported in recent years; therefore, new and effective strategies for treating schistosomiasis-induced hepatic fibrosis are urgently needed. MicroRNA (miRNA), a non-coding RNA, has been proved to be associated with the development of many human diseases, including schistosomiasis. In this review, we present a balanced and comprehensive view of the role of miRNAs in the pathogenesis, grading, and treatment of schistosomiasis-associated hepatic fibrosis. The multiple regulatory roles of miRNAs, such as promoting or inhibiting the development of liver pathology in murine schistosomiasis are also discussed in depth. Additionally, miRNAs may serve as candidate biomarkers for diagnosing liver pathology of schistosomiasis and as novel therapeutic targets for treating schistosomiasis-associated hepatic fibrosis.

Suppression of cell proliferation and collagen production in cultured human hypertrophic scar fibroblasts by Sp1 decoy oligodeoxynucleotide

Hypertrophic scars are characterized by the abnormal proliferation of fibroblasts and an overproduction of collagen. The Sp1 transcription factor is involved in the stimulation of collagen synthesis. A decoy oligonucleotide (ODN) targeting Sp1 was designed and transfected into hypertrophic scar fibroblasts (HSFs) cells using cationic liposomes. The transfection efficiency was determined by flow cytometry and was observed to be 85±7% (n=5). Specific binding of the Sp1 decoy ODN was monitored with an electrophoretic mobility shift assay (EMSA). Following transfection with the decoy ODN to Sp1, cell viability and cell proliferation, which were examined by the cell counting kit WST‑8, were decreased by 80% compared with untreated cells. Transforming growth factor‑β (TGF‑β) mRNA and collagen mRNA expression were also reduced by 48% in the transfection decoy ODN group. The cell viability of HSFs after 48 h of transfection with 25, 50, 100 and 150 nM Sp1 decoy ODN was 0.9331±0.0203, 0.7479±0.0868, 0.577±0.0347 and 0.4703±0.0147, respectively. The 100 nM dose of the Sp1 decoy ODN inhibited the expression of types I and III collagen by 32 and 28%, respectively (both P<0.01). TGF‑β mRNA expression was also effectively suppressed by the 100 nM Sp1 decoy ODN (P<0.01). The Sp1 decoy ODN inhibited cell proliferation and the expression of types I and III collagen. Therefore, Sp1 decoy ODNs may be a promising tool for developing and testing novel therapeutic applications for treating hypertrophic scars.

COL1A1 oligodeoxynucleotides decoy: biochemical and morphologic effects in an acute wound repair model

Type I collagen is an integral component of granulation tissue and scar, that is highly dependent on TGFβ1, a member of a pro-fibrotic family of cytokines, for its promotion and deposition. Blocking COL1A1 gene transcription obstructs type I collagen synthesis, hindering the progress of granulation tissue deposition and fibrosis. Local injections of a double stranded oligodeoxynucleotide (dsODN) decoy, containing the TGFβ1 regulatory element that is located in the distal promoter of the COL1A1 gene, were investigated in a rat polyvinyl alcohol (PVA) sponge granulation tissue implant model. The effects on the granulation tissue deposition by dsODN decoy therapy were evaluated by the synthesis of types I and III collagens as well as ED-A (cellular) fibronectin. Fluorescently labeled dsODN was used to identify the distribution of the decoy molecules in the sponge implant relative to the observed histological effects. Morphological alterations in cells and changes in the organization of connective tissue were documented and evaluated. Collagen levels were reduced by half in implants treated with 10 nM dsODN decoy compared to scrambled dsODN-treated implants. Histologically, dsODN decoy treated implants had an increased cellular density without a corresponding increase in deposited connective tissue. Polarized light birefringence pattern of Sirius red-stained sections showed less collagen fibers accumulating between fibroblasts. The highest concentration of fluorescently labeled dsODN was identified within the interior margin of sponge implants, correlating to increased cellular density and an altered birefringence patterns. In conclusion, 10 nM dsODN decoy therapy reduced collagen deposition and altered the organization of granulation tissue, supporting its potential as a localized anti-fibrotic therapy for limiting fibrotic conditions.

Oligodeoxynucleotide decoy therapy blocks type 1 procollagen transcription and the prolyl hydroxylase beta subunit translation

Persistent transforming growth factor-beta1 (TGF-beta1) exposure to lungs increases type 1 collagen synthesis and deposition resulting in excess fibrosis which leads to morbidity and possibly death. We now report using human embryonic lung fibroblasts in the presence of TGF-beta1, a novel double-stranded (ds) DNA decoy with phosphorothioate (PT) linkages, containing the TGF-beta cis-element found in the distal promoter region of the COL1A1 gene which silences COL1A1 gene expression. In a cell-free protein translation system, we have previously reported that collagen synthesis was inhibited by disulfide isomerase, the prolyl-4-hydroxylase (P-4-H) beta subunit. By comparative proteomics dsdecoy therapy increased the levels of disulfide isomerase, the P-4-H beta subunit. These findings taken together support the notion that the dsdecoy inhibits type 1 collagen synthesis at both the transcriptional and translational levels.

TGF-beta-induced fibrosis and SMAD signaling: oligo decoys as natural therapeutics for inhibition of tissue fibrosis and scarring

Transforming-growth factor-beta (TGF-beta) is a pleiotrophic growth factor that is synthesized by many cells in the body. This growth factor is chemotactic for fibroblasts, stimulates fibroblast proliferation, and increases the synthesis of a number of extracellular matrix proteins including collagens. The TGF-beta activator protein is a transacting factor, which binds to the TGF-beta element in the distal promoter of the COL1A1 collagen gene and induces transcription of this gene. Although transient TGF-beta 1 activity participates in repair and regeneration of tissues, persistent TGF-beta 1 function affects excessive fibrosis and ultimately scarring of both skin and internal organs. Scarring of internal organ (e.g., liver and lung) results in a loss of function and ultimately death may occur. The central issue of this review is that phosphorothioate double-stranded decoys or other decoys decrease procollagen gene expression, procollagen synthesis, and collagen during fibrogenesis. The rationale is that the decoys containing the TGF-beta element or other gene transcription regulatory CIS-elements bind the transacting proteins preventing the latter from binding to the CIS-element in the 5'-flanking region of the natural gene resulting in transcription inhibition. We will, in part, focus on aspects involved in TGF-beta 1-induced fibrosis that occur during fibrogenesis and the use of the dsTGF-beta element containing oligodeoxynucleotide decoys to control excessive collagen synthesis, and deposition resulting from persistent TGF-beta. In our model of regulation of collagen synthesis, these double-stranded oligo decoys act as promoter competitors, binding to the activator protein either in the cytoplasm or in the nucleus. The significance of the proposed studies is that these novel natural antifibrotics will mimic the effect of glucocorticoids on collagen synthesis during fibrogenesis without the unwanted side effects of these steroids. Based on our previous studies on the molecular mechanisms by which glucocorticoids selectively decrease collagen synthesis, designed phosphorothioate oligodeoxynucleotides resistant to nuclease action will mimic the effects of glucocorticoids at the molecular, cellular, and in vivo levels of collagen synthesis. However, the glucocorticoids significantly inhibit noncollagen protein synthesis. Both the single-stranded and double-stranded oligodeoxynucleotide specifically decrease collagen synthesis without an inhibitory effect on noncollagen protein synthesis. In this review, we will specifically ask if TGF-beta-induced collagen synthesis is inhibited in cell culture and in vivo by using the double-stranded oligodeoxynucleotide decoys, will this inhibit fibrogenesis and ultimately scarring?

Therapies for bleomycin induced lung fibrosis through regulation of TGF-β1 induced collagen gene expression

This review describes normal and abnormal wound healing, the latter characterized by excessive fibrosis and scarring, which for lung can result in morbidity and sometimes mortality. The cells, the extracellular matrix (ECM) proteins, and the growth factors regulating the synthesis, degradation, and deposition of the ECM proteins will be discussed. Therapeutics with particular emphasis given to gene therapies and their effects on specific signaling pathways are described. Bleomycin (BM), a potent antineoplastic antibiotic increases TGF-beta1 transcription, TGF-beta1 gene expression, and TGF-beta protein. Like TGF-beta1, BM acts through the same distal promoter cis-element of the COL1A1 gene causing increased COL1 synthesis and lung fibrosis. Lung fibroblasts exist as subpopulations with one subset predominantly responding to fibrogenic stimuli which could be a specific cell therapeutic target for the onset and development of pulmonary fibrosis.

Tissue fibrosis and carcinogenesis: divergent or successive pathways dictate multiple molecular therapeutic targets for oligo decoy therapies

The extracellular matrix (ECM) is composed of several families of macromolecular components: fibrous proteins such as collagens, type I collagen (COL1), type III collagen (COL3), fibronectin, elastin, and glycoconjugates such as proteoglycans and matrix glycoproteins. Their receptors on the cell membrane, most of which in the case of the ECM belong to the integrins, which are heterodimeric proteins composed of alpha and beta chains. COL1 is the major fibrous collagen of bone, tendon, and skin; while COL3 is the more pliable collagen of organs like liver. Focus will not only be given to the regulation of synthesis of several fibrogenic parameters but also modulation of their degradation during growth factor-induced tissue fibrosis and cancer development. Evidence will be provided that certain tissues, which undergo fibrosis, also become cancerous. Why does there exist a divergency between tissues, which undergo frank fibrosis as an endpoint, and those tissues that undergo fibrosis and subsequently are susceptible to carcinogenicity; resulting from the etiological factor(s) causing the initial injury? For example, why does a polyvinyl alcohol (PVA) sponge implant become encapsulated and filled with fibrous tissue then fibrosis tissue growth stops? Why does the subcutaneous injection of a fibrogenic growth factor cause a benign growth and incisional wounding results in fibrosis and ultimately scarring? There are many examples of tissues, which undergo fibrosis as a prerequisite to carcinogenesis. Is there a cause-effect relationship? If you block tissue fibrosis in these precancerous tissues, would you block cancer formation? What are the molecular targets for blocking fibrosis and ultimately carcinogenesis? How can oligo decoys may be used to attenuate carcinogenesis and which oligo decoys specifically attenuate fibrogenesis as a prelude to carcinogenesis? What are other molecular targets for oligo decoy therapy in carcinogenesis?