Subconjunctival antisense oligonucleotides targeting TNF-alpha influence immunopathology and viral replication in murine HSV-1 retinitis

Cyclosporine A-Loaded Nanocarriers for Topical Treatment of Murine Experimental Autoimmune Uveoretinitis

In the present study, tissue distribution and the therapeutic effect of topically applied cyclosporine A (CsA)-loaded methoxy-poly(ethylene-glycol)-hexyl substituted poly(lactic acid) (mPEGhexPLA) nanocarriers (ApidSOL) on experimental autoimmune uveitis (EAU) were investigated. The CsA-loaded mPEGhexPLA nanocarrier was tolerated well locally and showed no signs of immediate toxicity after repeated topical application in mice with EAU. Upon unilateral CsA treatment, CsA accumulated predominantly in the corneal and sclera-choroidal tissue of the treated eye and in lymph nodes (LN). This regimen reduced EAU severity in treated eyes compared to PBS-treated controls. This improvement was accompanied by reduced T-cell count, T-cell proliferation, and IL-2 secretion of cells from ipsilateral LN. In conclusion, topical treatment with CsA-loaded mPEGhexPLA nanocarriers significantly improves the outcome of EAU.

A Therapeutic Antiviral Antibody Inhibits the Anterograde Directed Neuron-to-Cell Spread of Herpes Simplex Virus and Protects against Ocular Disease

Herpes simplex virus (HSV) is a leading cause of blindness and viral encephalitis in the developed world. Upon reactivation from sensory neurons, HSV returns via axonal transport to peripheral tissues where it causes, e.g., severe, potentially blinding ocular diseases. In the present study we investigated whether the HSV-1/2 glycoprotein B-specific antibody mAb 2c or its humanized counterpart mAb hu2c can protect from ocular disease in a mouse model of HSV-1-induced acute retinal necrosis (ARN). In this model the viral spread from the initially infected to the contralateral eye resembles the routes taken in humans upon HSV reactivation. Systemic antibody treatment prior or early after infection effectively protected the mice from the development of ARN. These observations suggest that the antibody potently neutralized the infection and inhibited the viral transmission, since there was almost no virus detectable in the contralateral eyes and trigeminal ganglia of antibody treated mice. Besides of neutralizing free virus or limiting the infection via activating the complement or cellular effector functions, blocking of the anterograde directed neuron-to-cell spread of HSV represents a viable mode of action how mAb 2c protected the mice from ARN. We proved this hypothesis using a microfluidic chamber system. Neurons and epithelial cells were cultured in two separate compartments where the neurons sent axons via connecting microgrooves to the epithelial cells. Neurons were infected with a reporter HSV-1 strain expressing mCherry, and the co-culture was treated with neutralizing antibodies. In contrast to commercial polyclonal human HSV-neutralizing immunoglobulins, mAb 2c effectively blocked the anterograde directed neuron-to-cell transmission of the virus. Our data suggest that the humanized HSV-1/2-gB antibody protects mice from ocular disease by blocking the neuronal spread of HSV. Therefore, mAb hu2c may become a potent novel therapeutic option for severe ocular HSV infections.

Aptamer-based therapeutics of the past, present and future: from the perspective of eye-related diseases

Aptamers have emerged as a novel and powerful class of biomolecules with an immense untapped potential. The ability to synthesise highly specific aptamers against any molecular target make them a vital cog in the design of effective therapeutics for the future. However, only a minutia of the enormous potential of this dynamic class of molecule has been exploited. Several aptamers have been studied for the treatment of eye-related disorders, and one such strategy has been successful in therapy. This review gives an account of several eye diseases and their regulatory biomolecules where other nucleic acid therapeutics have been attempted with limited success and how aptamers, with their exceptional flexibility to chemical modifications, can overcome those inherent shortcomings.

Intravitreal treatment with antisense oligonucleotides targeting tumor necrosis factor-α in murine herpes simplex virus type 1 retinitis

BACKGROUND

Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine known to participate in intraocular inflammatory disease. This study investigated whether treatment with intravitreal antisense-oligonucleotides (ASON) targeting TNF-α mRNA affects the progression of herpes simplex virus 1 (HSV-1) retinitis in mice.

METHODS

The in vivo uptake of the oligonucleotid after intravitreal injection was determined with FITC-labeled TNF-α ASON. HSV-retinitis was induced on day 0 by the injection of HSV-1 (KOS strain) into the anterior chamber (AC) of the right eyes of BALB/c mice (von Szily model). The left contralateral eyes were injected intravitreally on day 7 with TNF-α ASON, sequence-unspecific control ASON (CON), or buffer. The clinical course of retinitis, ocular inflammatory cell-infiltration, TNF-α expression in the eye by ELISA, delayed-type hypersensitivity (DTH) reaction, virus-neutralizing antibody titers in the serum, uptake of [3H]thymidine from regional lymph node (rln) cells, and viral content in the eyes were determined.

RESULTS

In vivo, strong fluorescence of FITC- TNF-α ASON was detected in the choroid and retina up to 3 days after intravitreal injection, but none in the rln. After treatment of eyes with ASON, decreased expression of TNF-α in the eye, and reduced incidence and severity of retinitis on day 10 after infection (P < 0.05) could be found. The other parameters were not significantly influenced after TNF-α ASON treatment.

CONCLUSIONS

TNF-α participates in the pathology of HSV-1 retinitis. Local inhibition of TNF-α mRNA by intraocular TNF-α ASON injection did not influence the systemic HSV-specific immune response or the antiviral response in the eye, but reduced ocular inflammatory bystander damage.

Trans-scleral delivery of macromolecules

Non-invasive drug delivery to the posterior segment of the eye represents an important unmet medical need, and trans-scleral delivery could be an interesting solution. This review analyses the possibility of trans-scleral drug delivery for high molecular weight compounds, such as proteins and genetic material, which currently represent the most innovative and efficacious molecules for the treatment of many diseases of the posterior segment of the eye. The paper reviews all the barriers, both static and dynamic, involved in trans-scleral administration of drugs, trying to elucidate the role of each of them in the specific case of macromolecules. Delivery systems to sustain drug release and enhancing strategies to improve trans-scleral penetration are also described. Finally, the review approaches the use of computational models as a screening tool to evaluate the feasibility of trans-scleral administration for macromolecules.

Inhibition of HSV-1 ocular infection with morpholino oligomers targeting ICP0 and ICP27

Alternative therapies are needed for HSV-1 infections in patients refractory to treatment with Acyclovir (ACV) and its derivatives. Peptide-conjugated phosphorodiamidate morpholino oligomers (PPMO) are single-stranded DNA analogues that enter cells readily and reduce target gene expression through steric blockage of complementary RNA. When applied before or soon after infection PPMO targeting the translation-start-site regions of HSV-1 ICP0 or ICP27 mRNA reduced HSV-1 plaque formation by 70-98% in vitro. The ICP0 PPMO also reduced ACV-resistant HSV-1 (strain 615.9) plaque formation by 70-90%, while an equivalent dose of ACV produced only 40-50% inhibition when the treatment was applied between 1 and 3hpi. Seven daily topical treatments of 100microg ICP0 PPMO caused no gross or microscopic damage to the corneas of uninfected mice. Topical application of 10microg ICP0 PPMO to the eyes of HSV-1 infected mice reduced the incidence of eye disease by 37.5-50% compared to controls. This study demonstrates that topically applied PPMO holds promise as an antiviral drug candidate against HSV-1 ocular infection.

HSV-1 upregulates the ARE-binding protein tristetraprolin in a STAT1- and p38-dependent manner in mature dendritic cells

Dendritic cells are the sentinels of the immune system and as such represent the first-line of defense against incoming pathogens. Upon encounter with harmful antigens, these antigen-presenting cells start to mature and migrate towards the draining lymph nodes to display the antigen to T-lymphocytes, thereby eliciting the immune response of the host. Viruses, including human herpesvirus type I (HSV-1), seek to avoid such immune reactions. Therefore, they developed an arsenal of immune evasion strategies, some of which have been described earlier by our group and others. The secretion of tumor necrosis factor (TNF) represents a typical defense line of the host and it has been shown that this cytokine contributes to the inhibition of viral replication and augments the proliferation of cytotoxic T-lymphocytes. Here we report, that upon infection of mature dendritic cells, HSV-1 very strongly induces the expression of the AU-rich elements (ARE)-binding protein tristetraprolin (TTP), an mRNA-destabilizing protein. One of the best described targets of TTP is the TNF mRNA. This induction is dependent on the phosphorylation of both signal transducer and activator of transcription (STAT1) and p38 in a collaborative manner. By repressing this phosphorylation with specific inhibitors, we were able to reduce TTP mRNA levels. At the same time TNF mRNA levels were increased, suggesting that TNF mRNA is indeed a target of TTP in this setting. In summary, these data underline that HSV-1 induces TTP transcription in order to reduce TNF levels generated by infected mature dendritic cell.