In vitro analyses of the anti-fibrotic effect of SPARC silencing in human Tenon's fibroblasts: comparisons with mitomycin C

Dysregulated Genes and Signaling Pathways in the Formation and Rupture of Intracranial Aneurysm

Intracranial aneurysm (IA) has the potential to rupture. Despite scientific advances, we are still not in a position to screen patients for IA and identify those at risk of rupture. It is critical to comprehend the molecular basis of disease to facilitate the development of novel diagnostic strategies. We used transcriptomics to identify the dysregulated genes and understand their role in the disease biology. In particular, RNA-Seq was performed in tissue samples of controls, unruptured IA, and ruptured IA. Dysregulated genes (DGs) were identified and analyzed to understand the functional aspects of molecules. Subsequently, candidate genes were validated at both transcript and protein level. There were 314 DGs in patients with unruptured IA when compared to control samples. Out of these, SPARC and OSM were validated as candidate molecules in unruptured IA. PI3K-AKT signaling pathway was found to be an important pathway for the formation of IA. Similarly, 301 DGs were identified in the samples of ruptured IA when compared with unruptured IAs. CTSL was found to be a key candidate molecule which along with Hippo signaling pathway may be involved in the rupture of IA. We conclude that activation of PI3K-AKT signaling pathway by OSM along with up-regulation of SPARC is important for the formation of IA. Further, regulation of Hippo pathway through PI3K-AKT signaling results in the down-regulation of YAP1 gene. This along with up-regulation of CTSL leads to further weakening of aneurysm wall and its subsequent rupture.

SPARC Is Highly Expressed in Young Skin and Promotes Extracellular Matrix Integrity in Fibroblasts via the TGF-β Signaling Pathway

The matricellular secreted protein acidic and rich in cysteine (SPARC; also known as osteonectin), is involved in the regulation of extracellular matrix (ECM) synthesis, cell-ECM interactions, and bone mineralization. We found decreased SPARC expression in aged skin. Incubating foreskin fibroblasts with recombinant human SPARC led to increased type I collagen production and decreased matrix metalloproteinase-1 (MMP-1) secretion at the protein and mRNA levels. In a three-dimensional culture of foreskin fibroblasts mimicking the dermis, SPARC significantly increased the synthesis of type I collagen and decreased its degradation. In addition, SPARC also induced receptor-regulated SMAD (R-SMAD) phosphorylation. An inhibitor of transforming growth factor-beta (TGF-β) receptor type 1 reversed the SPARC-induced increase in type I collagen and decrease in MMP-1, and decreased SPARC-induced R-SMAD phosphorylation. Transcriptome analysis revealed that SPARC modulated expression of genes involved in ECM synthesis and regulation in fibroblasts. RT-qPCR confirmed that a subset of differentially expressed genes is induced by SPARC. These results indicated that SPARC enhanced ECM integrity by activating the TGF-β signaling pathway in fibroblasts. We inferred that the decline in SPARC expression in aged skin contributes to process of skin aging by negatively affecting ECM integrity in fibroblasts.

SPARC: a potential target for functional nanomaterials and drugs

Secreted protein acidic and rich in cysteine (SPARC), also termed osteonectin or BM-40, is a matricellular protein which regulates cell adhesion, extracellular matrix production, growth factor activity, and cell cycle. Although SPARC does not perform a structural function, it, however, modulates interactions between cells and the surrounding extracellular matrix due to its anti-proliferative and anti-adhesion properties. The overexpression of SPARC at sites, including injury, regeneration, obesity, cancer, and inflammation, reveals its application as a prospective target and therapeutic indicator in the treatment and assessment of disease. This article comprehensively summarizes the mechanism of SPARC overexpression in inflammation and tumors as well as the latest research progress of functional nanomaterials in the therapy of rheumatoid arthritis and tumors by manipulating SPARC as a new target. This article provides ideas for using functional nanomaterials to treat inflammatory diseases through the SPARC target. The purpose of this article is to provide a reference for ongoing disease research based on SPARC-targeted therapy.

Differential Gene and Protein Expression of Conjunctival Bleb Hyperfibrosis in Early Failure of Glaucoma Surgery

The early failure of glaucoma surgery is mainly caused by over-fibrosis at the subconjunctival space, causing obliteration of the filtration bleb. Because fibrosis has a suspected basis of genetic predisposition, we have undertaken a prospective study to identify upregulated profibrotic genes in a population of glaucoma patients with signs of conjunctival fibrosis and early postoperative surgical failure. Clinical data of re-operated fibrosis patients, hyperfibrosis patients who re-operated more than once in a short time, and control patients with no fibrosis were recorded and analyzed at each follow-up visit. Conjunctival-Tenon surgical specimens were obtained intraoperatively to evaluate the local expression of a panel of genes potentially associated with fibrosis. In order to correlate gene expression signatures with protein levels, we quantified secreted proteins in primary cultures of fibroblasts from patients. Expression of VEGFA, CXCL8, MYC, and CDKN1A was induced in the conjunctiva of hyperfibrosis patients. VEGFA and IL8 protein levels were also increased in fibroblast supernatants. We propose that an increase in these proteins could be useful in detecting conjunctival fibrosis in glaucoma patients undergoing filtering surgery. Molecular markers could be crucial for early detection of patients at high risk of failure of filtration surgery, leading to more optimal and personalized treatments.

SPARC-YAP/TAZ inhibition prevents the fibroblasts-myofibroblast transformation

BACKGROUND

Fibrotic scar is a severe side effect of trabeculectomy, resulting in unsatisfactory outcomes for glaucoma surgery. Accumulating evidence showed human Tenon's fibroblasts (HTFs) play an important role in fibrosis formation. We previously reported that the aqueous level of secreted protein acidic and rich in cysteine (SPARC) was higher in the patients with primary angle closure glaucoma, which was associated with the failure of trabeculectomy. In this study, the potential effect and mechanism of SPARC in promoting fibrosis were explored by using HTFs.

METHODS

HTFs were employed in this study and examined under a phase-contrast microscope. Cell viability was determined by CCK-8. The expressions of SPARC-YAP/TAZ signaling and the fibrosis-related markers were examined with reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), Western blot, and immunofluorescence, subcellular fractionation was conducted to further determined the variation of YAP and phosphorylated YAP. The differential gene expressions were analyzed with RNA sequencing (RNAseq), followed by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses.

RESULTS

Exogenous SPARC induced HTFs-myofibroblast transformation, as evidenced by the increased expression of α-SMA, collagen I and fibronectin in both protein and mRNA levels. SPARC knockdown decreased the expressions of the above genes in TGF-β2-treated HTFs. KEGG analysis showed that the Hippo signaling pathway was mostly enriched. SPARC treatment increased the expressions of YAP, TAZ, CTGF and CYR61 as well as enhanced YAP translocation from cytoplasm to nucleus, and decreased the phosphorylation of YAP and LAST1/2, which was reversed by SPARC knockdown. Knockdown of YAP1 decreased the fibrosis-related markers, such as α-SMA, collagen I and Fibronectin, in SPARC-treated HTFs.

CONCLUSIONS

SPARC induced HTFs-myofibroblast transformation via activating YAP/TAZ signaling. Targeting SPARC-YAP/TAZ axis in HTFs might provide a novel strategy for inhibiting fibrosis formation after trabeculectomy.

SPARC promotes fibroblast proliferation, migration, and collagen production in keloids by inactivation of p53

BACKGROUND

Keloid, an aggressive fibroproliferative disease of the skin, is usually caused by infectious skin diseases, burns, and trauma.

OBJECTIVE

This study aimed to assess the effect of SPARC on the keloid pathogenesis.

METHODS

In normal skin and keloid scar tissues, changes in SPARC expression were analysed by qRT-PCR, western blotting, and immunohistochemistry. Keloid fibroblasts were isolated from human keloid tissue. GSEA was performed to investigate the signalling pathways related to SPARC. Cell Counting Kit-8, 5-Ethynyl-2'-deoxyuridine, transwell assay, and scratching assays were used to assess fibroblast proliferation and migration. Changes in α-SMA, fibronectin, collagen I, and collagen III levels were examined in fibroblasts by western blotting.

RESULTS

SPARC expression was upregulated in keloid scar tissues. In fibroblasts, cell proliferation, migration, collagen production, and extracellular matrix (ECM) synthesis were promoted by SPARC overexpression, whereas SPARC knockdown resulted a converse result. GSEA showed that SPARC regulates the p53 pathway. In keloid scar tissues, there was a negative correlation between SPARC and p53 expression. p53 expression was decreased by SPARC overexpression, whereas SPARC knockdown increased p53 expression. Furthermore, the effects of SPARC on the fibroblast phenotype were reversed by p53 overexpression.

CONCLUSIONS

Fibroblast proliferation, migration, and ECM synthesis were promoted by SPARC overexpression, which was achieved by regulating the p53 pathway. Our findings provide new therapeutic targets for keloids.

Matrix Metalloproteinases and Glaucoma

Matrix metalloproteinases (MMPs) are enzymes that decompose extracellular matrix (ECM) proteins. MMPs are thought to play important roles in cellular processes, such as cell proliferation, differentiation, angiogenesis, migration, apoptosis, and host defense. MMPs are distributed in almost all intraocular tissues and are involved in physiological and pathological mechanisms of the eye. MMPs are also associated with glaucoma, a progressive neurodegenerative disease of the eyes. MMP activity affects intraocular pressure control and apoptosis of retinal ganglion cells, which are the pathological mechanisms of glaucoma. It also affects the risk of glaucoma development based on genetic pleomorphism. In addition, MMPs may affect the treatment outcomes of glaucoma, including the success rate of surgical treatment and side effects on the ocular surface due to glaucoma medications. This review discusses the various relationships between MMP and glaucoma.

Scar prevention through topical delivery of gelatin-tyramine-siSPARC nanoplex loaded in dissolvable hyaluronic acid microneedle patch across skin barrier

Currently, there is no effective method to prevent the formation of hypertrophic scars and keloids, which can cause severe physical and psychological burdens to patients. Secreted protein acidic and cysteine-rich (SPARC) is involved in wound fibrosis by modulating fibroblast functions, causing excessive collagen deposition during wound healing. Thus, the reduction in SPARC gene expression after wounding can contribute to the downstream reduction in collagen production at the wound site and prevent scar formation. In this study, a dissolvable and biocompatible hyaluronic acid (HA) microneedle patch loaded with nanoplexes containing tyramine-modified gelatin and siRNA for SPARC (siSPARC/Gtn-Tyr) was investigated for topical scar prevention. Tyramine-modified gelatin (Gtn-Tyr) provides electrostatic protection and enhances cell internalization for siSPARC. In vitro studies using human dermal fibroblasts showed that both siSPARC/Gtn-Tyr nanoplexes and siSPARC/Gtn-Tyr-loaded microneedle patches can significantly reduce SPARC gene expression (P < 0.05) and do not cause discernable cytotoxic effects. Further studies using a mouse wound model demonstrate that the siSPARC/Gtn-Tyr-loaded microneedle patch can reduce collagen production during wound healing without triggering an immune response. When Gtn-Tyr-siSPARC is administered transdermally at the wound site, effective collagen reduction is achieved through silencing of the matricellular SPARC protein, thus promising the reduction of scar formation. Overall, the siSPARC/Gtn-Tyr loaded microneedle patch can potentially provide an effective transdermal anti-fibrotic treatment.

Effects of Valproic Acid and Mitomycin C Combination Therapy in a Rabbit Model of Minimally Invasive Glaucoma Surgery

Purpose

This study aimed to compare the effectiveness of combination therapy consisting of low-dose mitomycin C (MMC) and valproic acid (VPA) against high-dose MMC for improving the scar phenotype in minimally invasive glaucoma surgery (MIGS).

Methods

A rabbit model of MIGS incorporating the PreserFlo MicroShunt was treated with high (0.4 mg/mL) or low (0.1 mg/mL) doses of MMC or with combination therapy consisting of low-dose (0.1 mg/mL) MMC and VPA. Operated eyes were examined by live ocular imaging, histochemical evaluation, multiphoton quantitation of collagen characteristics, and molecular analyses.

Results

Although high-dose MMC obliterated the vasculature, combination therapy vastly improved the postoperative tissue morphology by maintaining the vasculature without increased vascularization. Combination therapy also altered collagen morphology and reduced encapsulation of the MicroShunt distal end, which remained at risk with MMC treatment alone. Multiphoton quantitation indicated that the combination therapy significantly reduced collagen density and fiber dimensions compared with monotherapy. At the molecular level, combination therapy significantly reduced Vegfa, Vegfc, and Vegfd expression and inhibited Col1a1 upregulation from baseline levels, all of which low-dose MMC alone was unable to achieve. Notably, COL1A1 protein levels appeared more consistently suppressed by combination therapy compared with high-dose MMC alone.

Conclusions

Compared with high-dose MMC, combination therapy was less toxic by sparing the vasculature and potentially more effective in reducing scarring via the regulation of collagen content and organization.

Translational Relevance

VPA may be combined with low-dose MMC to replace high-dose MMC to deliver safe and effective anti-scarring outcomes.

SPARC knockdown attenuated TGF-β1-induced fibrotic effects through Smad2/3 pathways in human pterygium fibroblasts

PURPOSE

Secreted protein acidic and rich in cysteine (SPARC), a matricellular glycoprotein, has been found to regulate processes involved in fibrotic diseases. The aim of this study was to investigate the anti-fibrotic effects of SPARC in primary human pterygium fibroblasts (HPFs) and elucidate the underlying mechanisms.

METHODS

The expression of SPARC in HPFs was knocked down by RNA interference-based approach. Subsequently, we examined the expression of profibrotic markers induced by transforming growth factor-β1 (TGF-β1), including type 1 collagen (COL1), α-smooth muscle actin (α-SMA), and fibronectin (FN). The changes in signaling pathways and matrix metalloproteinases (MMPs) were also detected by western blotting. The cellular migration ability, proliferation ability, apoptosis, and contractile phenotype were detected using the wound healing assay, Cell Counting Kit-8 assay, flow cytometry, and collagen gel contraction assay, respectively. The interaction between SPARC and TGF-β RII was detected by Co-IP RESULTS: Silencing of SPARC inhibited the basal and TGF-β1-induced expression of COL1, α-SMA, and FN in HPFs, and suppressed the expression of p-Smad2, p-Smad3, Smad4 and MMP2, MMP9. The downregulation of SPARC also attenuated the cell migration and contractile phenotype of HPFs. SPARC could bind to TGF-βRII under TGF-β1 treatment. However, knockdown of SPARC did not affect the proliferation and apoptosis of HPFs.

CONCLUSION

SPARC knockdown attenuated the fibrotic effect induced by TGF-β1 at least in part by inactivating the Smad2/3 pathways in HPFs. Therefore, SPARC may be a promising therapeutic target for the treatment of pterygium.

Safety and efficacy of combination of suberoylamilide hydroxyamic acid and mitomycin C in reducing pro-fibrotic changes in human corneal epithelial cells

Corneal haze post refractive surgery is prevented by mitomycin c (MMC) treatment though it can lead to corneal endothelial damage, persistent epithelial defects and necrosis of cells. Suberanilohydroxamic acid (SAHA) however has been proposed to prevent corneal haze without any adverse effects. For clinical application we have investigated the short and long term outcome of cells exposed to SAHA. Human donor cornea, cultured limbal epithelial cells, corneal rims and lenticules were incubated with SAHA and MMC. The cells/tissue was then analyzed by RT-qPCR, immunofluorescence and western blot for markers of apoptosis and fibrosis. The results reveal that short term exposure of SAHA and SAHA + MMC reduced apoptosis levels and increased αSMA expression compared to those treated with MMC. Epithelial cells derived from cultured corneal rim that were incubated with the MMC, SAHA or MMC + SAHA revealed enhanced apoptosis, reduced levels of CK3/CK12, ∆NP63 and COL4A compared to other treatments. In SAHA treated lenticules TGFβ induced fibrosis was reduced. The results imply that MMC treatment for corneal haze has both short term and long term adverse effects on cells and the cellular properties. However, a combinatorial treatment of SAHA + MMC prevents expression of corneal fibrotic markers without causing any adverse effect on cellular properties.

Positive-charge tuned gelatin hydrogel-siSPARC injectable for siRNA anti-scarring therapy in post glaucoma filtration surgery

Small interfering RNA (siRNA) therapy is a promising epigenetic silencing strategy. However, its widespread adoption has been severely impeded by its ineffective delivery into the cellular environment. Here, a biocompatible injectable gelatin-based hydrogel with positive-charge tuned surface charge is presented as an effective platform for siRNA protection and delivery. We demonstrate a two-step synthesis of a gelatin-tyramine (Gtn-Tyr) hydrogel with simultaneous charge tunability and crosslinking ability. We discuss how different physiochemical properties of the hydrogel interact with siSPARC (siRNA for secreted protein, acidic and rich in cysteine), and study the positive-charge tuned gelatin hydrogel as an effective delivery platform for siSPARC in anti-fibrotic treatment. Through in vitro studies using mouse tenon fibroblasts, the positive-charge tuned Gtn-Tyr hydrogel shows sustained siSPARC cellular internalization and effective SPARC silencing with excellent biocompatibility. Similarly, the same hydrogel platform delivering siSPARC in an in vivo assessment employing a rabbit model shows an effective reduction in subconjunctival scarring in post glaucoma filtration surgery, and is non-cytotoxic compared to a commonly used anti-scarring agent, mitomycin-C. Overall, the current siRNA delivery strategy involving the positive-charge tuned gelatin hydrogel shows effective delivery of gene silencing siSPARC for anti-fibrotic treatment. The current charge tunable hydrogel delivery system is simple to fabricate and highly scalable. We believe this delivery platform has strong translational potential for effective siRNA delivery and epigenetic silencing therapy.

Treatment with Hyaluronic Acid and Collagen-Polyvinylpyrrolidone Improves Extracellular Matrix Assembly for Scarring after Tracheal Resection

Treatment of tracheal stenosis is occasionally performed in combination with wound healing modulators to manipulate new extracellular matrix (ECM) formation and prevent fibrosis. Hyaluronic acid (HA) and collagen-polyvinylpyrrolidone (collagen-PVP) decrease fibrosis in experimental tracheal healing. However, they have not been used clinically as their effect on ECM components, which modify tracheal scarring, has not been described. Objective. To evaluate the effect of the application of HA, collagen-PVP, a mixture of HA and collagen-PVP (HA+collagen-PVP), and mitomycin C on the expression of decorin, matrix metalloproteinase 1 (MMP1), and MMP9, as well as the type of collagen and deposits formed in the scar after resection and end-to-end anastomosis (REEA) of the cervical trachea using an experimental model. Materials and Methods. Thirty dogs underwent REEA of the cervical trachea and were treated with different wound healing modulators: group I (n = 6), control; group II (n = 6), HA; group III (n = 6), collagen-PVP; group IV (n = 6), HA+collagen-PVP; and group V (n = 6), mitomycin C. The dogs were evaluated clinically and endoscopically for 4 weeks. Subsequently, macroscopic and microscopic changes, expression of ECM proteins, and collagen deposition in tracheal scars were analysed. Results. Groups II, III, and IV showed reduced endoscopic, macroscopic, and microscopic inflammation, improved neovascularization, high decorin expression (p < 0.01, analysis of variance (ANOVA)), and moderate expression of MMP1 (p < 0.003, ANOVA) and type I and III collagen (p < 0.05, Kruskal–Wallis). Groups IV and V developed fewer collagen deposits (p < 0.001, ANOVA). Conclusion. Treatment with HA and collagen-PVP improved post-REEA healing by increasing neovascularization, stimulating the expression of decorin, and regulating the expression of MMP1, as well as type I and III collagen and their deposition.

SPARC Levels Modulate the Capacity of Mitomycin to Inhibit the Proliferation of Human Tenon's Capsule Fibroblasts

Purpose

To evaluate the role of SPARC in the antiproliferation effect of MMC on human Tenon's fibroblasts (HTF).

Method

Sixteen PACG patients aged 59 ± 10 years (31-72 years), including 6 males and 10 females, were recruited. Tenon tissue was harvested during filtering surgery. Cell density was evaluated after MMC application with different concentrations and application times, by which the optimized MMC application modality was determined. MMC, si-SPARC, or SPARC protein was used when needed to evaluate the cell densities under different conditions, by which the role of SPARC in MMC-mediated antifibrotic process was identified.

Results

Considering that the cell densities, as well as SPARC expression on mRNA and protein levels, are relatively stable when the MMC concentration is higher than 0.02% and exposure time longer than 90 s, we chose the MMC application pattern with 0.02% and 90 s as an optimized pattern for the downstream work. Compared to control, the si-SPARC and MMC downregulated the SPARC protein by 91% (P < 0.01) and 65% (P < 0.01) and 65% (P < 0.01) and 65% (P < 0.01) and 65% (P < 0.01) and 65% (P < 0.01) and 65% (P < 0.01) and 65% (P < 0.01) and 65% (.

Conclusion

This study demonstrates that in HTF, (1) MMC downregulates the expression of SPARC in protein and mRNA levels; (2) SPARC depletion has synergistic effect on the antifibrotic effect of MMC; and (3) reactive oxygen species are the possible mediator in the antifibrotic effect of MMC and si-SPARC.

The DNA topoisomerase II inhibitor amsacrine as a novel candidate adjuvant in a model of glaucoma filtration surgery

Treatments for refractory glaucoma include trabeculectomy, in which a filtering bleb is created to reduce aqueous pressure. Mitomycin C (MMC) is often used as an adjuvant to reduce post-trabeculectomy bleb scarring and consequent failure. However, scarring sometimes still occurs. Thus, we searched for more effective trabeculectomy adjuvants with high-throughput screening (HTS) of a library of 1,165 off-patent drug compounds. This revealed that amsacrine (AMSA), a DNA topoisomerase II (TOP2) inhibitor, was the top candidate. Compared to MMC, rabbits that underwent trabeculectomy with 10% AMSA had lower IOP at 42, 56, and 70 days (P < 0.01 at all measurement points) and a higher bleb score at 28, 42, 56, and 70 days (P =  < 0.01, 0.04, 0.04, and < 0.01, respectively). Compared to saline, rabbits that received 1% AMSA also had lower IOP and better bleb score at all time points, without a sharp drop in IOP just after surgery (all P < 0.01). Both effects were milder than MMC at 7 days (P = 0.02 and <0.01, respectively). Thus, this study showed that HTS may help identify new, promising uses for off-patent drugs. Furthermore, trabeculectomy with AMSA at a suitable concentration may improve the prognosis after trabeculectomy compared to MMC.

RelB regulates basal and proinflammatory induction of conjunctival CCL2

Purpose: This study investigated the involvement of NF-kB in regulating postoperative conjunctival inflammation.Methods: Experimental surgery was performed as described for the mouse model of conjunctival scarring. Expression of NF-κB in postoperative conjunctival tissues or conjunctival fibroblasts were assessed by real-time PCR, immunoblotting and immunofluorescence analyses. Downregulation of RelB was achieved using small interfering RNA. Cellular cytokine secretion was determined using multiplex cytokine assay.Results: RelB was the most highly induced member of the NF-kB family on day 2 post-surgery. Elevated RelB may be found associated with vimentin-positive cells and fibroblasts in vivo and in vitro. In conjunctival fibroblasts, RelB may be induced by TNF-α but not TGF-β2 while its silencing caused selective induction of CCL2 secretion by both basal and TNF-α-stimulated fibroblasts.Conclusions: High RelB induction in the inflammatory phase and the selective modulation of CCL2 suggest a specific anti-inflammatory role for RelB in the postoperative conjunctiva.

Matricellular Protein Levels in Aqueous Humor and Surgical Outcomes of Trabeculectomy

Purpose

The purpose of this study was to quantify levels of three matricellular proteins in the aqueous humor in patients with previous acute primary angle closure (APAC) and investigate their correlation with bleb morphology and surgical outcomes of trabeculectomy.

Methods

In this prospective study, aqueous humor samples were collected from 40 previous APAC eyes. Concentrations of three matricellular proteins-secreted protein acidic and rich in cysteine (SPARC), thrombospondin-2, and osteopontin-were measured using multiplexed immunoassays kits. Intraocular pressure was measured using Goldmann application tonometry. Bleb morphology was assessed using anterior segment optical coherence tomography, and bleb score was calculated according to bleb size and reflectivity.

Results

When previous APAC eyes were divided according to surgical outcome 18 months after trabeculectomy, SPARC protein was significantly higher in aqueous humor in the failure group (P = 0.009). When previous APAC eyes were divided according to SPARC level, eyes with low SPARC levels had significantly higher overall success rate compared with eyes with high SPARC levels (P = 0.005 for complete success and P = 0.018 for qualified success). Multiple logistic regression analyses showed that eyes with higher levels of SPARC were more likely to have a failed filtration surgery than were eyes with lower levels of SPARC. For complete success, P = 0.006 and odds ratio (OR) = 6.458; for qualified success, P = 0.033 and OR = 2.608. The level of SPARC was found to have a positive correlation with bleb score (P < 0.001, R2 = 0.471).

Conclusions

In previous APAC patients, the SPARC level in aqueous humor is a prognostic factor for surgical results of trabeculectomy. Modulation of SPARC expression may have potential clinical applications after filtration surgery.

The effectiveness of colchicine combined with mitomycin C to prolong bleb function in trabeculectomy in rabbits

Purpose

To investigate the potential of colchicine to improve bleb function after trabeculectomy.

Methods

To find the maximum usable colchicine concentration, an ocular irritation study was performed with the Draize test at concentrations of 0.001%, 0.01% and 0.1%. Additionally, the synergistic effect of topical colchicine instillation and MMC application to surgical site was evaluated in a rabbit model by measuring changes after trabeculectomy in intraocular pressure (IOP) and bleb morphology score at 3, 7, 14, 21, 28, 35, 42, and 49 days.

Results

Experiments with a rabbit model of trabeculectomy showed that 0.04% MMC plus 0.01% colchicine was more effective than saline and 0.04% MMC alone in maintaining IOP reduction at days 7–49 (P < 0.01 at all time points) and day 49 (P < 0.05), respectively, while 0.04% MMC alone was more effective than saline only at days 7–35 (P < 0.05 at all time points). 0.04% MMC plus 0.01% colchicine and 0.04% MMC alone were more effective than saline at preserving bleb score at days 7–21 and 35–49 (P < 0.05 at all time points) and at days 7–35 (P < 0.05 at all time points), respectively.

Conclusion

Colchicine may be a promising adjuvant for strengthening the effect of MMC and improving the survival of the filtering bleb in trabeculectomy.

Targeted therapy for the post-operative conjunctiva: SPARC silencing reduces collagen deposition

BACKGROUND

To develop targeted antifibrotic therapy for glaucoma filtration surgery; this study determines the effectiveness of small interfering RNA (siRNA) to reduce in vivo secreted protein acidic and rich in cysteine (SPARC) expression using the mouse model of conjunctival scarring.

METHODS

Experimental surgery was performed as described for the mouse model of conjunctival scarring. Scrambled (siScram) or Sparc (siSparc) siRNAs, loaded on layer-by-layer (LbL) nanoparticles, were injected into the conjunctiva immediately after surgery. Expression of Sparc, Col1a1, Fn1 and Mmp14 was measured by real-time PCR and immunoblotting on days 7 and 14 postsurgery. Live imaging of the operated eyes was performed using slit lamp, anterior segment-optical coherence tomography and confocal microscopy. Tissue pathology was evaluated by histochemical and immunofluorescent analyses of operated conjunctival cryosections. Tissue apoptosis was quantitated by annexin V assay. RESULTS : siSparc, delivered via expanded LbL nanoparticles, significantly inhibited Sparc transcription in both day 7 (2.04-fold) and day 14 (1.39-fold) treated tissues. Sparc suppression on day 7 was associated with a significant reduction of Col1a1 (2.52-fold), Fn1 (2.89-fold) and Mmp14 (2.23-fold) mRNAs. At the protein level, both SPARC and collagen 1A1 (COL1A1) were significantly reduced at both time points with siSparc treatment. Nanoparticles were visualised within cell-like structures by confocal microscopy, while overt tissue response or apoptosis was not observed. CONCLUSIONS : SPARC targeted therapy effectively reduced both SPARC and collagen production in the operated mouse conjunctiva. This proof-of-concept study suggests that targeted treatment of fibrosis in glaucoma surgery is safe and feasible, with the potential to extend to a range of potential genes associated with fibrosis.

Modulation of Fibroblasts in Conjunctival Wound Healing

Modulating conjunctival wound healing has the potential to improve outcomes after glaucoma filtration surgery and for several ocular disorders, including ocular cicatrial pemphigoid, vernal keratoconjunctivitis, and pterygium. Although anti-inflammatories and antimetabolites have been used with success, these nonspecific agents are not without their complications. The search for novel and more targeted means to control conjunctival fibrosis without such limitations has brought much attention to the regulation of fibroblast proliferation, differentiation, extracellular matrix production, and apoptosis. This review provides an update on where we stand with current antifibrotic agents and outlines the strategies that novel agents use, as they evolve from the bench to the bedside.

Upregulation of distinct collagen transcripts in post-surgery scar tissue: a study of conjunctival fibrosis

Excessive accumulation of collagen is often used to assess the development of fibrosis. This study aims to identify collagen genes that define fibrosis in the conjunctiva following glaucoma filtration surgery (GFS). Using the mouse model of GFS, we have identified collagen transcripts that were upregulated in the fibrotic phase of wound healing via RNA-seq. The collagen transcripts that were increased the most were encoded by Col8a1, Col11a1 and Col8a2. Further analysis of the Col8a1, Col11a1 and Col8a2 transcripts revealed their increase by 67-, 54- and 18-fold, respectively, in the fibrotic phase, compared with 12-fold for Col1a1, the most commonly evaluated collagen gene for fibrosis. However, only type I collagen was significantly upregulated at the protein level in the fibrotic phase. Type VIII and type I collagens colocalized in fibrous structures and in ACTA2-positive pericytes, and appeared to compensate for each other in expression levels. Type XI collagen showed low colocalization with both type VIII and type I collagens but can be found in association with macrophages. Furthermore, we show that both mouse and human conjunctival fibroblasts expressed elevated levels of the most highly expressed collagen genes in response to TGFβ2 treatment. Importantly, conjunctival tissues from individuals whose GF surgeries have failed due to scarring showed 3.60- and 2.78-fold increases in type VIII and I collagen transcripts, respectively, compared with those from individuals with no prior surgeries. These data demonstrate that distinct collagen transcripts are expressed at high levels in the conjunctiva after surgery and their unique expression profiles may imply differential influences on the fibrotic outcome.

Summary: As well as providing an objective quantitative measure, distinct collagen genes may further aid in the characterization and definition of the development of fibrosis.

Biological function and mechanism of lncRNA-MEG3 in Tenon's capsule fibroblasts proliferation: By MEG3-Nrf2 protein interaction

OBJECTIVE

The proliferation of Tenon's capsule fibroblasts after glaucoma filtration surgery is a harmful element for operation failure. However, the underlying mechanism remains unclear. In this study, we evaluated the role of long non-coding RNA (lncRNA)-MEG3 in the proliferation of Glaucoma Tenon's capsule fibroblasts (GTFs) with a model of transforming growth factor-β (TGF-β)-induced proliferation which has been used in previous studies to explore the mechanism underlying glaucoma surgery failure.

METHODS

In vitro cell proliferation model was made by TGF-β2 (5ng/mL)-stimulated GTFs obtained from patients with glaucoma filtration surgery, and cell viability and cell proliferation was assessed by MTT assay and [3H] thymidine incorporation assay respectively. Relative expression of MEG3 and Nrf2 mRNA was determined by quantitative real-time PCR. Nrf2 protein level was detected by western blot. Functional interaction between MEG3 and Nrf2 was examined by RNA pull down and RNA Binding Protein Immunoprecipitation (RIP).

RESULTS

As detected in isolated Tenon's capsule fibroblasts, expression level of both MEG3 and Nrf2 is decreased in GTFs compared with control fibroblasts (HTFs). Adenovirus mediated overexpression of MEG3 attenuates cell ability and cell proliferation, as well as contributed to upregulation of Nrf2 protein in TGF-β2-stimualted GTFs. MEG3 positively affects the expression of Nrf2 protein rather than Nrf2 mRNA. We found that this functional interaction of them depends on MEG3-Nrf2 protein formation by RNA pull down and RIP analysis and also is proved to be involved in TGF-β2-induced cell proliferation.

CONCLUSION

The above data suggested that the functional interaction between lncRNA-MEG3 and Nrf2 constitutes the mechanism by which TGF-β2 induces Tenon's capsule fibroblasts proliferation after glaucoma filtration surgery via the direct binding of MEG3 to Nrf2.

Anti-proliferative effect of olmesartan on Tenon's capsule fibroblasts

AIM

To evaluate the inhibitive effect of olmesartan to fibroblast proliferation and the anti-scarring effect in Tenon's capsule, both in vitro and in vivo.

METHODS

Human primary Tenon's capsule fibroblasts were cultured in vitro, treated with up titrating concentrations of olmesartan. The rate of inhibition was tested with methyl thiazol tetrazolium (MTT) method. Real-time PCR was performed to analyze changes in mRNA expressions of the fibrosis-related factors: matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase (TIMP-1,2) and proliferating cell nuclear antigen (PCNA). Thirty rabbits were divided into 5 groups (3, 7, 14, 21, and 28d). A rabbit conjunctiva flap model was created in each eye. Olmesartan solution was injected subconjunctivally and then evaluated its anti-proliferation and anti-fibrosis effects through the histological morphology and immunohistochemistry of MMP-2 and PCNA in each group. Only the 7d group was treated with Masson's trichrome to compare the neovascularization in the subconjunctiva area.

RESULTS

In vitro, cultured Tenon's capsule human fibroblasts showed a dose dependent inhibition by olmesartan in MTT. Olmesartan reduced mRNA expressions of MMP-2 and PCNA but increased mRNA expressions of TIMP-1 and TIMP-2. In vivo, the rabbit eyes treated with olmesartan at 3(rd), 7(th), 14(th) and 21(st) days demonstrated a significant reduced expressions of MMP-2 and PCNA compared with control eye, no significant difference observed in 28(th) day group. The cellular proliferation and neovascularization was suppressed by olmesartan in Masson's trichrome observation.

CONCLUSION

By inhibiting fibroblasts in vitro and in vivo, olmesartan prevents the proliferation and activity of fibroblasts in scar tissue formation, which might benefit glaucoma filtering surgery.

Pathobiology of wound healing after glaucoma filtration surgery

Conjunctival and subconjunctival fibrogenesis and inflammation are sight compromising side effects that can occur subsequent to glaucoma filtration surgery. Despite initial declines in intraocular pressure resulting from increasing aqueous outflow, one of the activated responses includes marshalling of proinflammatory and pro-fibrogenic cytokine mediator entrance into the aqueous through a sclerostomy window and their release by local cells, as well as infiltrating activated immune cells. These changes induce dysregulated inflammation, edema and extracellular matrix remodeling, which occlude outflow facility. A number of therapeutic approaches are being taken to offset declines in outflow facility since the current procedure of inhibiting fibrosis with either mitomycin C (MMC) or 5-fluorouracil (5-FU) injection is nonselective. One of them entails developing a new strategy for reducing fibrosis induced by wound healing responses including myofibroblast transdifferentiation and extracellular matrix remodeling in tissue surrounding surgically created shunts. The success of this endeavor is predicated on having a good understanding of conjunctival wound healing pathobiology. In this review, we discuss the roles of inappropriately activated growth factor and cytokine receptor linked signaling cascades inducing conjunctival fibrosis/scarring during post-glaucoma surgery wound healing. Such insight may identify drug targets for blocking fibrogenic signaling and excessive fibrosis which reduces rises in outflow facility resulting from glaucoma filtration surgery.

Valproic acid suppresses collagen by selective regulation of Smads in conjunctival fibrosis

Overproduction of type I collagen is associated with a wide range of fibrotic diseases as well as surgical failure such as in glaucoma filtration surgery (GFS). Its modulation is therefore of clinical importance. Valproic acid (VPA) is known to reduce collagen in a variety of tissues with unclear mechanism of action. In this report, we demonstrate that VPA inhibited collagen production in both conjunctival fibroblasts and the mouse model of GFS. In fibroblasts, VPA decreased type I collagen expression which intensified with longer drug exposure and suppressed steady-state type I collagen promoter activity. Moreover, VPA decreased Smad2, Smad3 and Smad4 but increased Smad6 expression with a similar intensity-exposure profile. Reduction of Smad3 using small hairpin RNA and/or overexpression of Smad6 resulted in decreased collagen expression which was exacerbated when VPA was simultaneously present. Furthermore, fibrogenic TGF-β2 failed to induce collagen when VPA was present, as opposed to the myofibroblast markers, beta-actin, alpha-smooth muscle actin and tenascin-C, which were elevated by TGF-β2. VPA suppressed p3TP-Lux luciferase activity and selectively rescued Smad6 expression from suppression by TGF-β2. Notably, SMAD6 overexpression reduced the effectiveness of TGF-β2 in inducing collagen expression. In corroboration, VPA inhibited type I collagen but increased Smad6 expression in the late phase of wound healing in the mouse model of GFS. Taken together, our data indicate that VPA has the capacity to effectively suppress both steady-state and fibrogenic activation of type I collagen expression by modulating Smad expression. Hence, VPA is potentially applicable as an anti-fibrotic therapeutic by targeting collagen. Key message: • VPA modulates type I collagen expression via members of the Smad family. • VPA suppresses Smad2, Smad3 and Smad4 but upregulates Smad6. • Smad3 and Smad6 are involved in VPA regulation of steady-state collagen expression. • Smad6 is involved in VPA modulation of TGF-β-stimulated collagen expression. • VPA reduces collagen and upregulates Smad6 in the mouse model of glaucoma filtration surgery.

Effects of ranibizumab on TGF-β1 and TGF-β2 production by human Tenon's fibroblasts: An in vitro study

PURPOSE

Inhibiting exaggerated wound healing responses, which are primarily mediated by human Tenon's fibroblast (HTF) migration and proliferation, has become the major determining factor for a successful trabeculectomy. Antivascular endothelial growth factor (anti-VEGF) has showed promising results as a potential antifibrotic candidate for use concurrently in trabeculectomy. Preliminary cohort studies have revealed improved bleb morphology following trabeculectomy augmented with ranibizumab. However, the effects on HTFs remain unclear. This study was conducted to understand the effects of ranibizumab on transforming growth factor (TGF)-β1 and transforming growth factor (TGF)-β2 expression by HTFs.

METHODS

The effect of ranibizumab on HTF proliferation and cell viability was determined using 3-(4,5-dimethylthiazone-2-yl)-2,5-diphenyl tetrazolium (MTT) assay. Ranibizumab at concentrations ranging from 0.01 to 0.5 mg/ml were administered for 24, 48, and 72 h in serum and serum-free conditions. Supernatants and cell lysates from samples were assessed for TGF-β1 and TGF-β2 mRNA and protein levels using quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

At 48 h, 0.5 mg/ml of ranibizumab significantly induced cell death under serum-free culture conditions (p<0.05). Ranibizumab caused a significant reduction in TGF-β1 mRNA, but not for TGF-β2. However, the total protein production of TGF-β1 and TGF-β2 was unaffected by this anti-VEGF treatment.

CONCLUSIONS

Exposure of HTFs to an intravitreal dose of ranibizumab significantly suppresses cell viability in vitro; however, the application seemed unable to affect the ultimate production of TGF-β. Therefore, we highlighted ranibizumab as a potential antiscarring agent that acts via a different mechanism when used synergistically with another antifibrotic agent. Understanding the mechanism of actions of ranibizumab offers an additional view of a possible new rational therapeutic strategy.

Developing novel anti-fibrotic therapeutics to modulate post-surgical wound healing in glaucoma: big potential for small molecules

Ocular fibrosis leads to significant visual impairment and blindness in millions of people worldwide, and is one of the largest areas of unmet need in clinical ophthalmology. The antimetabolites, mitomycin C and 5-fluorouracil, are the current gold standards used primarily to prevent fibrosis after glaucoma surgery, but have potentially blinding complications like tissue damage, breakdown and infection. This review thus focuses on the development of new classes of small molecule therapeutics to prevent post-surgical fibrosis in the eye, especially in the context of glaucoma filtration surgery. We discuss recent advances and innovations in ophthalmic wound healing research, including antibodies, RNAi, gene therapy, nanoparticles, liposomes, dendrimers, proteoglycans and small molecule inhibitors. We also review the challenges involved in terms of drug delivery, duration of action and potential toxicity of new anti-fibrotic agents in the eye.

Transcriptional dynamics of a conserved gene expression network associated with craniofacial divergence in Arctic charr

Background

Understanding the molecular basis of craniofacial variation can provide insights into key developmental mechanisms of adaptive changes and their role in trophic divergence and speciation. Arctic charr (Salvelinus alpinus) is a polymorphic fish species, and, in Lake Thingvallavatn in Iceland, four sympatric morphs have evolved distinct craniofacial structures. We conducted a gene expression study on candidates from a conserved gene coexpression network, focusing on the development of craniofacial elements in embryos of two contrasting Arctic charr morphotypes (benthic and limnetic).

Results

Four Arctic charr morphs were studied: one limnetic and two benthic morphs from Lake Thingvallavatn and a limnetic reference aquaculture morph. The presence of morphological differences at developmental stages before the onset of feeding was verified by morphometric analysis. Following up on our previous findings that Mmp2 and Sparc were differentially expressed between morphotypes, we identified a network of genes with conserved coexpression across diverse vertebrate species. A comparative expression study of candidates from this network in developing heads of the four Arctic charr morphs verified the coexpression relationship of these genes and revealed distinct transcriptional dynamics strongly correlated with contrasting craniofacial morphologies (benthic versus limnetic). A literature review and Gene Ontology analysis indicated that a significant proportion of the network genes play a role in extracellular matrix organization and skeletogenesis, and motif enrichment analysis of conserved noncoding regions of network candidates predicted a handful of transcription factors, including Ap1 and Ets2, as potential regulators of the gene network. The expression of Ets2 itself was also found to associate with network gene expression. Genes linked to glucocorticoid signalling were also studied, as both Mmp2 and Sparc are responsive to this pathway. Among those, several transcriptional targets and upstream regulators showed differential expression between the contrasting morphotypes. Interestingly, although selected network genes showed overlapping expression patterns in situ and no morph differences, Timp2 expression patterns differed between morphs.

Conclusion

Our comparative study of transcriptional dynamics in divergent craniofacial morphologies of Arctic charr revealed a conserved network of coexpressed genes sharing functional roles in structural morphogenesis. We also implicate transcriptional regulators of the network as targets for future functional studies.

Electronic supplementary material

The online version of this article (doi:10.1186/2041-9139-5-40) contains supplementary material, which is available to authorized users.

Small-interfering RNAs (siRNAs) as a promising tool for ocular therapy

RNA interference (RNAi) can be used to inhibit the expression of specific genes in vitro and in vivo, thereby providing an extremely useful tool for investigating gene function. Progress in the understanding of RNAi-based mechanisms has opened up new perspectives in therapeutics for the treatment of several diseases including ocular disorders. The eye is currently considered a good target for RNAi therapy mainly because it is a confined compartment and, therefore, enables local delivery of small-interfering RNAs (siRNAs) by topical instillation or direct injection. However, delivery strategies that protect the siRNAs from degradation and are suitable for long-term treatment would be help to improve the efficacy of RNAi-based therapies for ocular pathologies. siRNAs targeting critical molecules involved in the pathogenesis of glaucoma, retinitis pigmentosa and neovascular eye diseases (age-related macular degeneration, diabetic retinopathy and corneal neovascularization) have been tested in experimental animal models, and clinical trials have been conducted with some of them. This review provides an update on the progress of RNAi in ocular therapeutics, discussing the advantages and drawbacks of RNAi-based therapeutics compared to previous treatments.

IL-6 as a corneal wound healing mediator in an in vitro scratch assay

Corneal healing process under inflammatory conditions is not fully understood. We aimed at determining the effect of an inflammatory (presence of IL-6) or anti-inflammatory (presence of IL-10) environment and a mixture of both in the expression of IL-6 signaling pathway mediators, and on corneal wound healing in an in vitro scratch assay. For that purpose, human corneal epithelial cells were cultured until confluence. The effect of IL-6 (10 ng/ml), IL-10 (20 ng/ml) or IL-6 + IL-10 exposure on the expression of IL-6R, gp130, and STAT3 was determined by Western blotting and quantitative PCR, at different time points. The monolayer was mechanically wounded using a sterile 10 μl pipette tip. Wound healing rate in the presence or absence of these cytokines was measured immediately after cytokine exposure and after 4, 8, and 24 h. The effect of mitomycin C on wound healing rate, in control and IL-6-stimulated cells, was also evaluated. Detection of proliferative cells was performed with an EdU imaging kit. For the visualization of migrating cells, cold methanol-fixed cells were incubated with an α-actinin antibody. For the statistical analysis a two-factor design of experiment method was applied. Levene test was used to contrast equality of variances. If variances were equal, ANOVA was performed to test the equality of means. If variances were not equal, a Mood's median test was performed. We observed that IL-6 and IL-10 stimulation, and their combination, increased gp130 production at different time points. STAT3 production was increased in IL-6-stimulated cells, at 72 h. An increase in pSTAT3 production was found in IL-6- and IL-10-stimulated cells, that was sustained in time in IL-6 + IL-10 co-stimulated cultures. Scraped areas had an initial width of 570.57 ± 75.82 μm. In IL-6-exposed cells wound healing closure was faster than in control cells or IL-10-exposed cells. After 8 h, wound width in IL-10-exposed cells, was also significantly smaller than that of control cells. Cells exposed to IL-6 + IL-10 had the slowest wound healing rate, similar to control cells. Wounds were closed after 24 h regardless the experimental condition. Mitomycin C exposure increased the wound closure rate in every experimental condition. No significant differences in the percentage of proliferative cells at the edge of the scratch and in distant areas of the monolayer were found. At the edge of the scratch, some actin filaments of non-proliferative cells were directed through the cell-free area, independently of the stimulating condition. In conclusion, the presence of IL-10 and, most importantly, of IL-6, increased the wound healing rate in an in vitro corneal wound healing model. The combination of both cytokines did not have a synergistic action in wound healing. In our model, wound closure was the result of the combination of cell proliferation and cell migration.

Layer-by-layer nanoparticles as an efficient siRNA delivery vehicle for SPARC silencing

Efficient and safe delivery systems for siRNA therapeutics remain a challenge. Elevated secreted protein, acidic, and rich in cysteine (SPARC) protein expression is associated with tissue scarring and fibrosis. Here we investigate the feasibility of encapsulating SPARC-siRNA in the bilayers of layer-by-layer (LbL) nanoparticles (NPs) with poly(L-arginine) (ARG) and dextran (DXS) as polyelectrolytes. Cellular binding and uptake of LbL NPs as well as siRNA delivery were studied in FibroGRO cells. siGLO-siRNA and SPARC-siRNA were efficiently coated onto hydroxyapatite nanoparticles. The multilayered NPs were characterized with regard to particle size, zeta potential and surface morphology using dynamic light scattering and transmission electron microscopy. The SPARC-gene silencing and mRNA levels were analyzed using ChemiDOC western blot technique and RT-PCR. The multilayer SPARC-siRNA incorporated nanoparticles are about 200 nm in diameter and are efficiently internalized into FibroGRO cells. Their intracellular fate was also followed by tagging with suitable reporter siRNA as well as with lysotracker dye; confocal microscopy clearly indicates endosomal escape of the particles. Significant (60%) SPARC-gene knock down was achieved by using 0.4 pmole siRNA/μg of LbL NPs in FibroGRO cells and the relative expression of SPARC mRNA reduced significantly (60%) against untreated cells. The cytotoxicity as evaluated by xCelligence real-time cell proliferation and MTT cell assay, indicated that the SPARC-siRNA-loaded LbL NPs are non-toxic. In conclusion, the LbL NP system described provides a promising, safe and efficient delivery platform as a non-viral vector for siRNA delivery that uses biopolymers to enhance the gene knock down efficiency for the development of siRNA therapeutics.

Differential effects of erufosine on proliferation, wound healing and apoptosis in colorectal cancer cell lines

The alkylphosphocholine, erucylphospho-N,N, N-trimethylpropanolamine (erufosine), has demonstrated anticancer effects in various cell lines, including leukemia, multiple myeloma, bladder, breast and oral squamous cell carcinoma cells. The purpose of the present study was to investigate its antiproliferative, antimigratory and pro-apoptotic effects in colorectal cancer cell lines, SW480 and CC531. The antiproliferative effect was determined by (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) (MTT) dye reduction assay following exposure to erufosine (3.1-100 µM) for 24-72 h. The antimigratory effect of erufosine (1.6-6 µM) was investigated by a wound healing assay for 12-48 h. Caspase-3/-7 activity was measured to detect apoptotic cell death. Erufosine inhibited cell proliferation in a dose- and time-dependent manner. The IC50 values following 72 h of incubation were 3.4 and 25.4 µM for SW480 and CC531 cells, respectively. erufosine at concentrations of 50 and 100 µM induced caspase-3/-7 activity concentration-dependently in SW480 cells, but only at 100 µM in CC531 cells. Incubation of SW480 cells with erufosine (1.56 µM) for 48 h inhibited migration into the scratched area by 54% as compared to the untreated cells; whereas in CC531 cells, the wound width in the erufosine-treated (1.56-6.25 µM) cells following 48 h was closed 2-fold slower than the rate in the untreated group. Erufosine (25 µM) attenuated osteonectin expression and abolished COL1A1 expression in CC531 cells. Erufosine appears to be a promising treatment agent for colorectal cancer. Rat CC531 cells are less sensitive to erufosine than human SW480 cells.

Validation of reference genes for expression studies during craniofacial development in arctic charr

Arctic charr (Salvelinus alpinus) is a highly polymorphic species and in Lake Thingvallavatn, Iceland, four phenotypic morphs have evolved. These differences in morphology, especially in craniofacial structures are already apparent during embryonic development, indicating that genes important in the formation of the craniofacial features are expressed differentially between the morphs. In order to generate tools to examine these expression differences in Arctic charr, the aim of the present study was to identify reference genes for quantitative real-time PCR (qPCR). The specific aim was to select reference genes which are able to detect very small expression differences among different morphs. We selected twelve candidate reference genes from the literature, identified corresponding charr sequences using data derived from transcriptome sequencing (RNA-seq) and examined their expression using qPCR. Many of the candidate reference genes were found to be stably expressed, yet their quality-rank as reference genes varied considerably depending on the type of analysis used. In addition to commonly used software for reference gene validation, we used classical statistics to evaluate expression profiles avoiding a bias for reference genes with similar expression patterns (co-regulation). Based on these analyses we chose three reference genes, ACTB, UB2L3 and IF5A1 for further evaluation. Their consistency was assessed in an expression study of three known craniofacially expressed genes, sparc (or osteonectin), matrix metalloprotease 2 (mmp2) and sox9 (sex-determining region Y box 9 protein) using qPCR in embryo heads derived from four charr groups at three developmental time points. The three reference genes were found to be very suitable for studying expression differences between the morphotypes, enabling robust detection of small relative expression changes during charr development. Further, the results showed that sparc and mmp2 are differentially expressed in embryos of different Arctic charr morphotypes.

The expression of SPARC in human intracranial aneurysms and its relationship with MMP-2/-9

Objective

SPARC is a key determinant of invasion and metastasis in some tumors, such as gliomas, melanomas and prostate tumors. SPARC can change the composition and structure of the matrix and promote angiogenesis; these effects are closely related to clinical stage and the prognosis of tumors such as meningiomas. However, little is known about the expression of SPARC in intracranial aneurysms. The goal of this study was to establish the role of SPARC in human intracranial aneurysms.

Methods

Thirty-one intracranial aneurysms were immunohistochemically stained for SPARC, MMP-2 and MMP-9. As controls, normal Circle of Willis arteries were similarly immunostained. All specimens were retrieved during autopsies and were embedded in paraffin. To evaluate the expression levels of SPARC, MMP-2 and MMP-9, western blotting was also performed in three available intracranial aneurysm specimens. The limited availability of fresh intracranial aneurysm tissue was the result of the majority of patients choosing endovascular embolization.

Results

The results showed that SPARC, MMP-2 and MMP-9 were strongly expressed in intracranial aneurysm tissues; however, these proteins were expressed minimally or not at all in normal Circle of Willis arteries. The western blot results showed that the expression levels of SPARC, MMP-2 and MMP-9 were significantly up-regulated in intracranial aneurysms relative to the expression levels in the normal Circle of Willis arteries. Data analysis showed that SPARC was significantly correlated with MMP-2 and MMP-9, also with age and risk factors but not with the Hunt-Hess grade or with sex.

Conclusion

The results indicate that SPARC is widely expressed in human intracranial aneurysms, and its expression correlates with MMP-2 and MMP-9 expression, age and risk factors but not with the Hunt-Hess grade. The results of this study suggest that SPARC has a pathogenic role in the alteration of the extracellular matrix of intracranial arteries during aneurysm formation.

The Function of SPARC as a Mediator of Fibrosis

Fibrosis is a common end-point of a number of different diseases such as hypertension, diabetes, liver cirrhosis, and those associated with chronic inflammation. Fibrosis is characterized by excessive deposition of extracellular matrix that interferes with normal tissue architecture and function. Increased expression of secreted protein acidic and rich in cysteine (SPARC) in fibrotic tissues has been reported in numerous studies. SPARC is a 43 kDa collagen-binding protein secreted from several different cell types into the extracellular matrix and has been shown to be anti-proliferative and counter-adhesive in vitro. SPARC is a matricellular protein; meaning SPARC is secreted into the extracellular space but does not serve a structural function. Instead, SPARC modulates interactions between cells and the surrounding extracellular matrix. In animal models of fibrotic disease and in human fibrotic tissues, elevated expression of SPARC has been reported in many tissues including heart, lungs, kidneys, liver, dermis, intestine, and eyes. In this review, we will summarize current studies that have examined the expression and functional importance of SPARC in various animal models of fibrosis and in human tissues. Although cellular mechanisms of SPARC in fibrosis remain to be fully elucidated, the studies summarized here provide impetus to further explore the efficacy of SPARC as a potential target for reducing fibrosis.