Everolimus improves experimental autoimmune uveoretinitis

Autoimmunity and Carcinogenesis: Their Relationship under the Umbrella of Autophagy

The immune system and autophagy share a functional relationship. Both innate and adaptive immune responses involve autophagy and, depending on the disease’s origin and pathophysiology, it may have a detrimental or positive role on autoimmune disorders. As a “double-edged sword” in tumors, autophagy can either facilitate or impede tumor growth. The autophagy regulatory network that influences tumor progression and treatment resistance is dependent on cell and tissue types and tumor stages. The connection between autoimmunity and carcinogenesis has not been sufficiently explored in past studies. As a crucial mechanism between the two phenomena, autophagy may play a substantial role, though the specifics remain unclear. Several autophagy modifiers have demonstrated beneficial effects in models of autoimmune disease, emphasizing their therapeutic potential as treatments for autoimmune disorders. The function of autophagy in the tumor microenvironment and immune cells is the subject of intensive study. The objective of this review is to investigate the role of autophagy in the simultaneous genesis of autoimmunity and malignancy, shedding light on both sides of the issue. We believe our work will assist in the organization of current understanding in the field and promote additional research on this urgent and crucial topic.

Pharmacological insights into autophagy modulation in autoimmune diseases

As a cellular bulk degradation and survival mechanism, autophagy is implicated in diverse biological processes. Genome-wide association studies have revealed the link between autophagy gene polymorphisms and susceptibility of autoimmune diseases including systemic lupus erythematosus (SLE) and inflammatory bowel disease (IBD), indicating that autophagy dysregulation may be involved in the development of autoimmune diseases. A series of autophagy modulators have displayed protective effects on autoimmune disease models, highlighting the emerging role of autophagy modulators in treating autoimmune diseases. This review explores the roles of autophagy in the autoimmune diseases, with emphasis on four major autoimmune diseases [SLE, rheumatoid arthritis (RA), IBD, and experimental autoimmune encephalomyelitis (EAE)]. More importantly, the therapeutic potentials of small molecular autophagy modulators (including autophagy inducers and inhibitors) on autoimmune diseases are comprehensively analyzed.

HPLC-MS/MS-based analysis of everolimus in rabbit aqueous humor: pharmacokinetics of in situ gel eye drops of suspension

Aim: Everolimus is an inhibitor of mTOR which is derived from rapamycin. Its high corneal permeability and bioavailability makes it an effective treatment for ocular disorders. To study the pharmacokinetics of in situ gel eye drops of everolimus suspension after ocular administration in rabbit aqueous humor, we developed a rapid and reliable HPLC-MS/MS method. Methodology/results: Ascomycin was selected as the internal standard. HPLC-MS/MS method was used to investigate the concentration-time relationship of everolimus in rabbit aqueous humor through protein precipitation technique. The validated results showed good linearity, accuracy and precision. Conclusion: The method developed in this study is rapid, sensitive and reliable for the determination of the concentration of everolimus in rabbit aqueous humor.

Tolerance Induction in Relation to the Eye

Inflammatory intraocular eye diseases, grouped under the term uveitis are blinding conditions, believed to be mediated by pathogenic autoimmune processes that overcome the protective mechanisms of the immune privilege status of the eye. An animal model for these diseases, named experimental autoimmune uveitis (EAU), is induced by initiation of immunity against ocular-specific antigens, or it develops spontaneously in mice with T-cells that transgenically express TCR specific to the target eye antigen(s). T-Cells specific to ocular antigens are generated in the thymus and their majority are eliminated by exposure to their target antigen expressed in this organ. T-cells that escape this negative selection acquire pathogenicity by their activation with the target antigen. In spontaneous EAU, the microbiota play crucial roles in the acquisition of pathogenicity by providing both antigenic stimulation, by molecules that mimic the target ocular antigen, and an additional stimulation that allows invasion of tissues that harbor the target antigen. The pathogenic process is physiologically inhibited by the peripheral tolerance, composed of antigen-specific T-regulatory (Treg) lymphocytes. Deleting the Tregs enhances the ocular inflammation, whereas adoptively transferring them suppresses the pathogenic response. Potential usage of Treg cells for suppression of autoimmune diseases in humans is under intensive investigation.

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.

Novel everolimus-loaded nanocarriers for topical treatment of murine experimental autoimmune uveoretinitis (EAU)

In the present study, therapeutic effect of topically applied everolimus (EV)-loaded methoxy-poly(ethylene-glycol)-hexyl substituted poly (lactic acid) (mPEGhexPLA) nanocarriers on experimental autoimmune uveoretinitis (EAU) were investigated. EAU was induced in B10.RIII mice via immunization with human interphotoreceptor retinoid-binding protein peptide 161-180 (hIRBPp161-180) in complete Freund's adjuvant. Everolimus-loaded mPEGhexPLA (EV/mPEGhexPLA) nanocarriers were prepared by using a solvent evaporation method. On days 12-21 postimmunization (p.i.), the right eyes were treated five times daily either with 10 μl of 0.5% everolimus formulation or PBS (control). The EAU score of the eyes was determined histologically. On day 21 p.i., the peripheral immune responses were measured in serum, cervical lymph nodes (LN), and spleens via hIRBPp161-180-specific serum antibodies, cytokine secretion (ELISA), lymphocyte proliferation, and FoxP3+ regulatory T cells (Treg; flow cytometry). Compared to the PBS-treated mice, unilateral topical everolimus treatment significantly reduced EAU severity in both eyes (p < .05). The treatment reduced the antigen (Ag)-specific hIRBPp161-180-induced proliferation (p < .05), IL-2, IL-17, and IFN-γ secretion from cells isolated from the left and right cervical LN (p < .05). Under everolimus treatment, IL-10 secretion and CD4⁺CD25⁺FoxP3⁺ Treg frequency from cervical LN were enhanced. The proliferative response and cytokine secretion as well as the frequency of splenic Treg were almost unchanged. Topical administration of an everolimus formulation improved EAU in both eyes. The effect might also be related to systemic immunosuppressive effects, as several systemic cellular immune responses were influenced.

Evaluation of the Effect of Everolimus on Retinal Pigment Epithelial Cells and Experimental Proliferative Vitreoretinopathy

PURPOSE

Failure of retinal detachment surgery is most commonly due to the development of proliferative vitreoretinopathy (PVR). Everolimus is an inhibitor of mammalian target of rapamycin (mTOR), and is available as oral tablets. In this study, we investigated the effect of everolimus on retinal pigment epithelial cells and modification of the severity of experimental PVR.

METHODS

In our in vitro studies, primary culture of retinal pigment epithelium (RPE) cells was obtained from pigmented Rex rabbits. Cell proliferation was assayed with the tetrazolium dye cytotoxicity test, and cell migration assay was performed in 24-well transwell units with 8-μm filters. In the in vivo study, pigmented Rex rabbits weighing between 2 and 2.5 kg were used. Each rabbit eye underwent gas compression; one week later, 5 × 10⁴ RPE cells were injected into the vitreous cavity to induce PVR, and each eye was graded with indirect ophthalmoscopy on days 1, 3, 7, 14, 21, and 28. The rabbits were administered everolimus (0.5 mg/day orally) from the day of PVR induction. Total proteins extracted from RPE cells and dissected retinal samples were processed for Western blotting analysis of mTOR and ribosomal protein S6 (RPS6).

RESULTS

The in vitro studies showed that everolimus significantly inhibited the proliferation of RPE cells at 0.1 μg/ml; additionally, at 10 μg/ml, it suppressed the migration of RPE cells and significantly suppressed the expression of mTOR and RPS6 in RPE cells. The in vivo study did not show any benefit of oral everolimus (0.5 mg/day) in suppressing experimental PVR. Thus, everolimus significantly suppressed the expression of mTOR and RPS6 in PVR.

CONCLUSIONS

Everolimus suppressed the proliferation and migration of RPE cells in vitro. Oral everolimus (0.5 mg/day) suppressed the expression of mTOR and RPS6 in the retina, but showed no effect in suppressing experimental PVR.

Controlled Release of Second Generation mTOR Inhibitors to Restrain Inflammation in Primary Immune Cells

Autoimmune disease occurs when the immune system incorrectly targets the body's own tissue. Inflammatory CD4⁺ T cell phenotypes, such as T_H1 and T_H17, are key drivers of this attack. Recent studies demonstrate treatment with rapamycin-a key inhibitor of the mTOR pathway-can skew T cell development, moving T cell responses away from inflammatory phenotypes and toward regulatory T cells (T_REGS). T_REGS are important in inducing and maintaining tolerance to self-antigens, creating new potential to treat autoimmune diseases more effectively and specifically. Next generation analogs of rapamycin, such as everolimus and temsirolimus, confer increased potency with reduced toxicity, but are understudied in the context of autoimmunity. Further, these drugs are still broadly-acting and require frequent treatment due to short half-lives. Thus, there is strong interest in harnessing the unique properties of biomaterials-controlled drug release and targeting, for example, to improve autoimmune therapies. Using second generation mTOR inhibitors and rapamycin, we prepared sets of degradable polymer particles from poly(lactide-co-glycolide). We then used these materials to assess physicochemical properties and the ability to control autoimmune inflammation in a primary cell co-culture model. Treatment with particle formulations resulted in significant dose-dependent decreases in dendritic cell activation, T cell proliferation, inflammatory cytokines, and frequencies of inflammatory T_H1 phenotypes. Considering the current limitations of rapamycin, and the potential of next-generation analogs, this work provides a screening platform for biomaterials and sets the stage for in vivo evaluation, where delivery kinetics, stability, and targeting could improve autoimmune therapies through biomaterial-enabled delivery.

Rapamycin ameliorates CCl4-induced liver fibrosis in mice through reciprocal regulation of the Th17/Treg cell balance

Previous investigations have suggested that the activation of Th17 cells and/or deficiency of regulatory T cells (Tregs) are involved in the pathogenesis of liver fibrosis. The aim of the present study was to investigate the effect of rapamycin on immune responses in a carbon tetrachloride (CCl₄)-induced murine liver fibrosis model. Liver fibrosis was induced by intraperitoneal administration with CCl₄. Following injection of CCl₄, the mice were treated intraperitoneally with rapamycin (1.25 mg/kg/day) for 8 weeks. Hematoxylin and eosin staining and Masson's trichrome staining were used for histological examination. The protein levels of forkhead/winged helix transcription factor P3, retinoic-acid-related orphan receptor (ROR)-γt in liver tissue were determined by western blotting, the frequency of Th17 and Treg cells in the liver was evaluated by flow cytometry, and a suppression assay was measured by incorporating [3H]-thymidine. In addition, to explore the effect of Tregs expanded with rapamycin on hepatic stellate cells (HSC), HSCs were co-cultured with Tregs from rapamycin or phosphate-buffered saline-treated mice. It was found that rapamycin treatment led to a significant reduction in the number of Th17 cells and in the expression levels of ROR-γt in the liver tissues. Simultaneously, the results of the present study showed a significant increase in the frequency of Tregs and a marked enhancement in the expression of forkhead/winged helix transcription factor P3 in the rapamycin-treated mice. Furthermore, the Tregs in rapamycin-treated mice had significantly higher suppressive effects, compared with the cells from mice treated with phospphate-buffered saline. Consequently, rapamycin treatment prevented the development of CCl₄-induced hepatic fibrosis, which was shown by its histological appearances. These results suggested that the immunosuppressive effect of rapamycin on liver fibrosis was associated with the suppression of hepatic fibrogenesis and regulation of the Th17/Treg cell balance.

The effects of topical everolimus and sunitinib on corneal neovascularization

PURPOSE

To evaluate the effects of topical everolimus and sunitinib on corneal neovascularization (CNV).

METHODS

CNV was induced by application of silver nitrate to the cornea for all groups. Rats were divided into four groups of 10 rats each, and two corneas were obtained from each rat. Group I received 1 mg/ml everolimus, Group II received 0.5 mg/ml sunitinib, Group IV received no treatment (control group) and Group IV received 1% Dimethylsulfoxide (DMSO). All treatments were administrated twice daily for 2 weeks. The right corneas were used for extracellular signal-regulated kinase 1/2 (ERK 1/2) protein analysis by western blot analysis and the left corneas were used for ERK 1/2 and vascular endothelial growth factor-receptor (VEGFR-2) gene expression analysis by quantitative real-time PCR.

RESULTS

VEGFR-2 mRNA expression levels (ΔCt, median, min-max) were reduced in the everolimus 1.0 (0.25-1.81) and sunitinib 1.06 (0.24-2.68) treated groups compared with the control 4.74 (1.02-14.74) and DMSO groups 7.41 (0.72-13.10). The expression of ERK 1/2 protein and mRNA levels were reduced in everolimus group compared with the control group (p < 0.05). These differences were not seen between the sunitinib and control groups.

CONCLUSION

Topical administration of both everolimus and sunitinib reduced VEGFR-2 levels and inhibited CNV. In additon, everolimus reduced ERK 1/2 levels and seems to be more effective than sunitinib on CNV.

Prevention of herpes simplex virus induced stromal keratitis by a glycoprotein B-specific monoclonal antibody

The increasing incidence of acyclovir (ACV) and multidrug-resistant strains in patients with corneal HSV-1 infections leading to Herpetic Stromal Keratitis (HSK) is a major health problem in industrialized countries and often results in blindness. To overcome this obstacle, we have previously developed an HSV-gB-specific monoclonal antibody (mAb 2c) that proved to be highly protective in immunodeficient NOD/SCID-mice towards genital infections. In the present study, we examined the effectivity of mAb 2c in preventing the immunopathological disease HSK in the HSK BALB/c mouse model. Therefore, mice were inoculated with HSV-1 strain KOS on the scarified cornea to induce HSK and subsequently either systemically or topically treated with mAb 2c. Systemic treatment was performed by intravenous administration of mAb 2c 24 h prior to infection (pre-exposure prophylaxis) or 24, 40, and 56 hours after infection (post-exposure immunotherapy). Topical treatment was performed by periodical inoculations (5 times per day) of antibody-containing eye drops as control, starting at 24 h post infection. Systemic antibody treatment markedly reduced viral loads at the site of infection and completely protected mice from developing HSK. The administration of the antiviral antibody prior or post infection was equally effective. Topical treatment had no improving effect on the severity of HSK. In conclusion, our data demonstrate that mAb 2c proved to be an excellent drug for the treatment of corneal HSV-infections and for prevention of HSK and blindness. Moreover, the humanized counterpart (mAb hu2c) was equally effective in protecting mice from HSV-induced HSK when compared to the parental mouse antibody. These results warrant the future development of this antibody as a novel approach for the treatment of corneal HSV-infections in humans.

A comprehensive review and update on the non-biologic treatment of adult noninfectious uveitis: part I

INTRODUCTION

Treatment of adult, noninfectious uveitis remains a challenge for ophthalmologists around the world. The disease accounts for almost 10% of preventable blindness in the US and can be idiopathic or associated with infectious and systemic disorders. Strong evidence is still emerging to indicate that pharmacologic strategies presently used in rheumatologic or autoimmune disease may be translated to the treatment of intraocular inflammation. Corticosteroid monotherapy is widely regarded as wholly inappropriate, due to the unfavorable risk/benefit profile and poor long-term outcomes. Treatment plans have shifted away from low-dose, chronic corticosteroid therapy for maintenance, towards medium- to high-dose therapy for acute inflammation, followed immediately by initiation of immunomodulatory therapy. These therapies follow the 'stepladder approach', whereby least to more aggressive therapies are trialed to induce remission of inflammation, eventually without corticosteroids of any form (topical, local and systemic).

AREAS COVERED

This two-part review gives a comprehensive overview of the existing medical treatment options for patients with adult, noninfectious uveitis, as well as important advances for the treatment of ocular inflammation. Part I covers classic immunomodulation and latest information on corticosteroid therapy.

EXPERT OPINION

The hazard of chronic corticosteroid use for the treatment of adult, noninfectious uveitis is well-documented. Corticosteroid-sparing therapies, which offer a very favorable risk-benefit profile when administered properly, should be substituted.

Vertical inhibition of PI3K/Akt/mTOR signaling demonstrates in vitro and in vivo anti-fibrotic activity

BACKGROUND

The mammalian target of rapamycin (mTOR) regulates cellular activity in many diseases, but the complex interplay with PI3K/Akt pathway may hampers its function.

OBJECTIVE

This study was undertaken to determine the activity of PI3K/Akt/mTOR signaling in the fibroblasts from systemic sclerosis (SSc) patients, and compare the effects of vertical inhibiting PI3K/Akt/mTOR by BEZ235 and inhibiting mTOR alone by rapamycin in fibroblast activation and in two complementary established mouse model of SSc.

METHODS

Pharmaceutical specific inhibitors BEZ235 and rapamycin were used to vertical inhibit PI3K/Akt/mTOR signaling and mTOR signaling alone in cultured fibroblasts and in mice. SSc mouse model was established by daily injecting bleomycin subcutaneously or by overexpression of constitutively active type I TGF-β receptor (TβRI(ca)). To delineate the mechanisms underlying the antifibrotic effects of BEZ235 and rapamycin, activity of PI3K/Akt/mTOR signaling was analyzed by determining the expressions of phosphorylated Akt, GSK-3β, mTOR and S6 ribosomal protein (S6).

RESULTS

Primary dermal fibroblasts demonstrated hyperactivity of PI3K/Akt and mTOR signaling. mTOR inhibitor rapamycin failed to inhibit dermal fibrosis in an established SSc mouse model. However, administration of a dual inhibitor for PI3K/Akt and mTOR signaling BEZ235 attenuated dermal fibrosis by reversing increased dermal thickness and collagen deposition in two SSc mouse models. Furthermore, BEZ235 showed superior inhibitory effect on fibroblast activation relative to rapamycin in vitro. Also both BEZ235 and rapamycin could prevent the phosphorylation of mTOR and S6 completely. BEZ235 also blocked the activation of Akt and GSK-3β dramatically, whereas rapamycin has been shown to increase further upregulation of phosphorylated Akt on Ser473 both in vitro and in vivo.

CONCLUSION

These data show that blocking PI3K/Akt/mTOR with BEZ235 leads to superior inhibitory effect for dermal fibrosis, suggesting that vertical inhibition of PI3K/Akt/mTOR signaling may have therapeutic potential for SSc.