Protective effects of the galectin-1 protein on in vivo and in vitro models of ocular inflammation

PURPOSE

Galectin-1 (Gal-1) is a β-galactoside-binding protein with diverse biological activities in the pathogenesis of inflammation but has been poorly investigated in terms of ocular inflammation. In the present study, we monitored the anti-inflammatory effects of Gal-1 using the in vivo rodent model of endotoxin-induced uveitis (EIU) and in vitro assays with human RPE (ARPE-19) cells.

METHODS

For this purpose, EIU was induced by subcutaneous sterile saline injection of 0.1 ml of lipopolysaccharide (LPS, 1 mg/Kg) in the rat paw, which was maintained under these conditions for 24 h. The therapeutic efficacy of recombinant Gal-1 (rGal-1) was tested in the EIU animals by intraperitoneal inoculation (3 µg/100 µl per animal) 15 min after the LPS injection. In vitro studies were performed using LPS-stimulated ARPE-19 cells (10 μg/ml) for 2, 8, 24 and 48 h, treated or not with rGal-1 (4 μg/ml) or dexamethasone (Dex, 1.0 μM).

RESULTS

Gal-1 treatment attenuated the histopathological manifestation of EIU via the inhibition of polymorphonuclear cells (PMN) infiltration in the eye and by causing an imbalance in adhesion molecule expression and suppressing interleukin (IL)-1β, IL-6, and monocyte chemotactic protein-1 (MCP-1) productions. Immunohistochemical and western blotting analyses revealed significant upregulation of Gal-1 in the eyes induced by EIU after 24 h. In the retina, there was no difference in the Gal-1 expression, which was high in all groups, demonstrating its structural role in this region. To better understand the effects of Gal-1 in the retina, in vitro studies were performed using ARPE-19 cells. Ultrastructural immunocytochemical analyses showed decreased levels of endogenous Gal-1 in LPS-stimulated cells (24 h), while Dex treatment upregulated this protein. The protective effects of rGal-1 on LPS-stimulated cells were associated with the significant reduction of the release of cytokines (IL-8 and IL-6), similar to Dex treatment. Furthermore, rGal-1 and Dex inhibited cyclooxygenase-2 (COX-2) expression in LPS-stimulated cells, as shown by immunofluorescence.

CONCLUSIONS

Overall, this study identified potential roles for Gal-1 in ocular inflammation, especially uveitis, and may lead to future therapeutic approaches.

Anti-inflammatory or proinflammatory effect of an adenosine receptor agonist on the Th17 autoimmune response is inflammatory environment-dependent

Adenosine is a key endogenous signaling molecule that regulates a wide range of physiological functions, including immune system function and inflammation. Studies have shown that adenosine receptor (AR) agonists can be either anti-inflammatory or proinflammatory in immune responses and in inflammation, and the clarification of the mechanisms causing these opposing effects should provide a better guide for therapeutic intervention. Whereas previous studies mostly examined the effects of AR agonists on Th1-type immune responses, in this study, we compared their effect on Th17 and Th1 autoimmune responses in experimental autoimmune uveitis, a mouse model of human uveitis induced by immunization with the human interphotoreceptor retinoid-binding protein peptides 1-20. We showed that injection of mice with a nonselective AR agonist, 5'-N-ethylcarboxamidoadenosine (NECA), at an early stage after immunization had an inhibitory effect on both Th1 and Th17 responses, whereas injection of the same amount of NECA at a late stage inhibited the Th1 response but had an enhancing effect on the Th17 response. We also showed that the effects of NECA on Th1 and Th17 responses were completely dissociated, that the enhancing effect of NECA on Th17 responses was modulated by γδ T cells, and that the response of γδ T cells to NECA was determined by their activation status. We conclude that the inflammatory environment has a strong impact on converting the effect of AR agonist on the Th17 autoimmune response from anti-inflammatory to proinflammatory. Our observation should help in the designing of better AR-targeted therapies.

Randomized pharmacokinetic evaluation of different rifabutin doses in African HIV- infected tuberculosis patients on lopinavir/ritonavir-based antiretroviral therapy

BACKGROUND

Pharmacokinetic interactions between rifampicin and protease inhibitors (PIs) complicate the management of HIV-associated tuberculosis. Rifabutin is an alternative rifamycin, for patients requiring PIs. Recently some international guidelines have recommended a higher dose of rifabutin (150 mg daily) in combination with boosted lopinavir (LPV/r), than the previous dose of rifabutin (150 mg three times weekly {tiw}). But there are limited pharmacokinetic data evaluating the higher dose of rifabutin in combination with LPV/r. Sub-optimal dosing can lead to acquired rifamycin resistance (ARR). The plasma concentration of 25-O-desacetylrifabutin (d-RBT), the metabolite of rifabutin, increases in the presence of PIs and may lead to toxicity.

METHODS AND RESULTS

Sixteen patients with TB-HIV co-infection received rifabutin 300 mg QD in combination with tuberculosis chemotherapy (initially pyrazinamide, isoniazid and ethambutol then only isoniazid), and were then randomized to receive isoniazid and LPV/r based ART with rifabutin 150 mg tiw or rifabutin 150 mg daily. The rifabutin dose with ART was switched after 1 month. Serial rifabutin and d-RBT concentrations were measured after 4 weeks of each treatment. The median AUC0-48 and Cmax of rifabutin in patients taking 150 mg rifabutin tiw was significantly reduced compared to the other treatment arms. Geometric mean ratio (90% CI) for AUC0-48 and Cmax was 0.6 (0.5-0.7) and 0.5 (0.4-0.6) for RBT 150 mg tiw compared with RBT 300 mg and 0.4 (0.4-0.4) and 0.5 (0.5-0.6) for RBT 150 mg tiw compared with 150 mg daily. 86% of patients on the tiw rifabutin arm had an AUC0-24 < 4.5 μg.h/mL, which has previously been associated with acquired rifamycin resistance (ARR). Plasma d-RBT concentrations increased 5-fold with tiw rifabutin dosing and 15-fold with daily doses of rifabutin. Rifabutin was well tolerated at all doses and there were no grade 4 laboratory toxicities. One case of uveitis (grade 4), occurred in a patient taking rifabutin 300 mg daily prior to starting ART, and grade 3 neutropenia (asymptomatic) was reported in 4 patients. These events were not associated with increases in rifabutin or metabolite concentrations.

CONCLUSIONS

A daily 150 mg dose of rifabutin in combination with LPV/r safely maintained rifabutin plasma concentrations in line with those shown to prevent ARR.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00640887.

Uveitis: the collaborative diagnostic evaluation

Uveitis, or inflammation of the uveal tract (i.e., iris, ciliary body, and choroid), results from a heterogeneous collection of disorders of varying etiologies and pathogenic mechanisms. Uveitis is caused by a systemic disease in 30% to 45% of patients. Primary care physicians may be asked to evaluate patients with uveitis when an underlying systemic diagnosis is suspected but not apparent from eye examination or history. If the history, physical examination, and basic laboratory studies do not suggest an underlying cause, serologic tests for syphilis and chest radiography for sarcoidosis and tuberculosis are recommended. Typing for human leukocyte antigen-B27 is appropriate for patients with recurrent anterior uveitis. Because the prevalence of many rheumatologic and infectious diseases is low among persons with uveitis, Lyme serology, antinuclear antibody tests, serum angiotensin-converting enzyme tests, serum lysozyme tests, and tuberculin skin tests can result in false-positive results and are not routinely recommended. Drug-induced uveitis is rare and can occur from days to months after the time of initial exposure. Primary ocular lymphoma should be considered in persons older than 50 years with persistent intermediate or posterior uveitis that does not respond to anti-inflammatory therapy.

Ocular toxicity in BRAF mutant cutaneous melanoma patients treated with vemurafenib

PURPOSE

To determine the frequency of ocular adverse effects associated with vemurafenib (PLX4032) treatment for metastatic cutaneous melanoma.

DESIGN

Retrospective review of the clinical study reports from the clinical pharmacology, phase 1, phase 2, and phase 3 trials of vemurafenib.

METHODS

The vemurafenib clinical trials were a multicenter series involving adult patients with histologically confirmed, BRAF(V600) mutation-positive, unresectable, stage IIIC or IV melanoma. A total of 855 patients were enrolled in the trials: 568 patients were treated with vemurafenib and 287 patients were treated with dacarbazine.

RESULTS

Among the 568 patients treated with vemurafenib, ocular adverse effects developed in 22% (95% confidence interval [CI], 18.5-25.6). The most common ocular diagnosis was uveitis (4.0%; 95% CI, 2.6-6.0), followed by conjunctivitis (2.8%; 95% CI, 1.6-4.5) and dry eyes (2.0%; 95% CI, 1.1-3.7). All were successfully managed while vemurafenib therapy was continued.

CONCLUSIONS

Ocular adverse events and symptoms may be seen in more than one-fifth of patients being treated with vemurafenib. However, vemurafenib can be continued while the ocular symptoms are being managed. The pathogenesis of ocular symptoms in this patient population is unclear; additional studies are necessary.

Green tea extract treatment alleviates ocular inflammation in a rat model of endotoxin-induced uveitis

Green tea extract (GTE) ingested by rats exerted anti-oxidative activities in various ocular tissues as shown in our previous studies. The present work investigated anti-inflammatory effects of GTE on endotoxin-induced uveitis (EIU). EIU was generated in adult rats by a footpad injection of 1 mg/kg lipopolysaccharide (LPS). Oral administration of GTE (550 mg/kg) was given one, two or four times after LPS injection. Twenty-four hours later, LPS produced severe hyperemia and edema in the iris. Immunocytochemical examinations showed an accumulation of infiltrating cells in the aqueous humor that were immunopositive for cluster of differentiation 43 (CD43) and CD68, markers for leucocytes and macrophages, respectively. Analyses of the aqueous humor showed an increase in pro-inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1). GTE treatments improved the clinical manifestations and reduced infiltrating cells and protein exudation in the aqueous humor, which were not observed under half dose of GTE (275 mg/kg). The number of CD68 positive macrophages residing in the iris and ciliary was also reduced. GTE suppressed production of TNF-α, IL-6 and MCP-1 in the aqueous humor, which was associated with a down-regulation of LPS receptor complex subunits, Toll-like receptor 4 (TLR-4) and CD14, and suppression of nuclear factor-kappa Bp65 (NF-κBp65) in the iris and ciliary body. Our findings show that GTE is a potent anti-inflammatory agent against the inflammation of EIU, and suggest a potential use in treatment of acute uveitis.

[Alternation of retinal complement system in a mouse model of lipopolysaccharide- induced uveitis]

OBJECTIVE

To investigate the activation of the complement system in the retina in a mouse model of endotoxin-induced uveitis (EIU).

METHODS

Balb/c mice were randomly divided into control group and lipopolysaccharide (LPS)-induced EIU group. Twenty-four hours after modeling, the expressions of the major complement components of the classical pathway (CP), mannose-binding lectin (MBL) pathway, alternative pathway (AP), and terminal pathway in the retina were determined by quantitative RT-PCR. Western blotting was employed to examine the protein expressions of the key components of the complement system involved in the CP and AP pathways in the retina.

RESULTS

s Normal mouse retina expressed a variety of complement components that were involved mainly in the CP and AP pathways. The expressions of the complement components involved in the CP and AP pathways were up-regulated in the retina of mice with EIU. Although MASP1 and MASP2 were detected in the retina in both the EIU and control groups, their expressions were weak and showed no significant difference between the two groups.

CONCLUSION

The AP and CP but not the MBL pathways of the complement system are activated in the retina of mice with EIU, suggesting a role of the activated complement system in the pathological process of EIU.

An anti-interleukin-2 receptor drug attenuates T- helper 1 lymphocytes-mediated inflammation in an acute model of endotoxin-induced uveitis

The aim of the present study was to evaluate the anti-inflammatory efficacy of Daclizumab, an anti-interleukin-2 receptor drug, in an experimental uveitis model upon a subcutaneous injection of lipopolysaccharide into Lewis rats, a valuable model for ocular acute inflammatory processes. The integrity of the blood-aqueous barrier was assessed 24 h after endotoxin-induced uveitis by evaluating two parameters: cell count and protein concentration in aqueous humors. The histopathology of all the ocular structures (cornea, lens, sclera, choroid, retina, uvea, and anterior and posterior chambers) was also considered. Enzyme-linked immunosorbent assays of the aqueous humor samples were performed to quantify the levels of the different chemokine and cytokine proteins. Similarly, a biochemical analysis of oxidative stress-related markers was also assessed. The inflammation observed in the anterior chamber of the eyes when Daclizumab was administered with endotoxin was largely prevented since the aqueous humor protein concentration substantially lowered concomitantly with a significant reduction in the uveal and vitreous histopathological grading. Th1 lymphocytes-related cytokines, such as Interleukin-2 and Interferon-γ, also significantly reduced with related anti-oxidant systems recovery. Daclizumab treatment in endotoxin-induced uveitis reduced Th1 lymphocytes-related cytokines, such as Interleukin-2 and Interferon gamma, by about 60–70% and presented a preventive role in endotoxin-induced oxidative stress. This antioxidant protective effect of Daclizumab may be related to several of the observed Daclizumab effects in our study, including IL-6 cytokine regulatory properties and a substantial concomitant drop in INFγ. Concurrently, Daclizumab treatment triggered a significant reduction in both the uveal histopathological grading and protein concentration in aqueous humors, but not in cellular infiltration.

Roscovitine suppresses CD4+ T cells and T cell-mediated experimental uveitis

Background

T cells are essential for the development of uveitis and other autoimmune diseases. After initial activation, CD4+ lymphocytes express the co-stimulatory molecule OX40 that plays an important role in T cell proliferation. Cyclin dependent kinase 2 (CdK2) plays a pivotal role in the cell cycle transition from G1 to S phase. In addition, recent research has implicated CdK2 in T cell activation. Thus, we sought to test the immunosuppressive effect of roscovitine, a potent CdK2 inhibitor, on CD4+ T cell activation, proliferation, and function.

Design and Methods

Mouse CD4+ T cells were activated by anti-CD3 and anti-CD28 antibodies. The expression of OX40, CD44, and CdK2 were analyzed by flow cytometry. In addition, cell cycle progression and apoptosis of control and roscovitine-treated T lymphocytes were measured by BrdU incorporation and annexin V assay, respectively. Furthermore, the immunoregulatory effect of roscovitine was evaluated in both ovalbumin-induced uveitis and experimental autoimmune uveitis (EAU) models.

Results

In this study, we found that T cell activation induced OX40 expression. Cell cycle analysis showed that more CD4+OX40+ cells entered S phase than OX40- T cells. Concurrently, CD4+OX40+ cells had a higher level of CdK2 expression. Roscovitine treatment blocked activated CD4+ cells from entering S phase. In addition, roscovitine not only reduced the viability of CD4+ lymphocytes but also suppressed T cell activation and cytokine production. Finally, roscovitine significantly attenuated the severity of T cell-dependent, OX40-enhanced uveitis.

Conclusion

These results implicate CdK2 in OX40-augmented T cell response and expansion. Furthermore, this study suggests that roscovitine is a novel, promising, therapeutic agent for treating T cell-mediated diseases such as uveitis.

Topically applied standardized aqueous extract of Curcuma longa Linn. suppresses endotoxin-induced uveal inflammation in rats

Aqueous extract of C. longa when administered 4 h after induction of E. coli lipopolysaccharide-induced uveitis in rats showed significantly suppressed inflammation with a significantly lower mean clinical grade, histopathological grade and aqueous humor (AH) protein level compared to vehicle treated group. Although, prednisolone group showed significantly lower clinical grade, histopathological grades and AH protein levels compared to C. longa group, TNF-alpha levels did not differ significantly. Moreover, when the aqueous extract was administered starting from 3 days before induction of uveitis, the mean clinical and histopathological grade as well as AH protein and TNF-alpha levels were comparable to C. longa group when treatment was administered 4 h after induction of uveitis. It is concluded that topically applied standardized aqueous extract of C. longa suppresses endotoxin-induced uveitis in rats by reducing TNF-alpha activity.

Piceatannol suppresses endotoxin-induced ocular inflammation in rats

Anti-inflammatory effect of piceatannol, a naturally occurring polyphenol and a potent free radical scavenger, on ocular inflammation is not known. We examined the anti-inflammatory role of piceatannol in ocular inflammatory response due to endotoxin-induced uveitis (EIU) in rats. EIU was induced in Lewis rats by subcutaneous injection of lipopolysaccharide (LPS; 150 ug/rat). Piceatannol (30mg/kg body wt, i.p) was injected either 2h prior to or 1h post LPS induction. A significant increase in the number of infiltrating cells, total protein, and various cytokines and chemokines in AqH were observed in the EIU rat eyes as compared to control groups. However, pre- or post-treatment of piceatannol significantly blocked the LPS-induced changes. Further, piceatannol also suppressed the expression of cyclooxygenase-2 (Cox-2), inducible nitric oxide synthase (iNOS) and activation of NF-κB in the ciliary bodies as well as retina. Further, piceatannol also inhibited the expression of Cox-2, iNOS, and phosphorylation of NF-κB in primary human non-pigmented ciliary epithelial cells (HNPECs) treated with LPS. Similarly, piceatannol also diminished LPS-induced level of NO and prostaglandin E2 in HNPECs. Thus our results demonstrate an anti-inflammatory role of piceatannol in suppressing ocular inflammation induced by endotoxin in rats.

[Pharmacological pseudo-Fuchs]

CASE REPORT

A case of unilateral iridis hyperpigmentation and uveitis due to travoprost is presented.

DISCUSSION

Anterior uveitis is a rare side-effect of travoprost. In this case, heterochromic iris was also presented, which led us to the wrong diagnosis of a Fuchs heterochromic iridocyclitis. The differencial diagnosis along with the associated literature is discussed.

[Study on inhibitory effect of lycium pigment on lipopolysaccharide-induced uveitis in rats and its mechanism]

OBJECTIVE

To investigate the inhibitory effect of lycium pigment on lipopolysaccharide (LPS)-induced uveitis in rats and its mechanism.

METHOD

The rat uveitis model was established by 30-day oral administration of lycium pigment (50, 100, 200 mg x kg(-1)) and footpad injection of LPS. Ocular tissues were collected for a histopathological inspection. The protein, nitric oxide and ADMA in aqueous humor, level of inducible nitric oxide synthase (iNOS) in retina, activities of serum total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), and content of malondialdehyde (MDA) were determined by using Western blot, ELISA and biochemical methods.

RESULT

According to the pathological study, lycium pigment (50, 100, 200 mg x kg(-1)) could notably reduce the inflammatory cell infiltration around corpus ciliare matrix of uveitis rats, and the concentration of protein and nitric oxide, and increased ADMA in aqueous humor. Lycium pigment (100, 200 mg x kg(-1)) could significantly inhibit the expression of iNOS in ocular tissues. In addition, lycium pigment (100, 200 mg x kg(-1)) also decrease the activities of serum T-AOC, SOD, GSH-PX, and the content of lipid peroxide MDA.

CONCLUSION

Lycium pigment has the inhibitory effect on LPS-induced uveitis in rats. Its mechanism is related to the regulation of nitric oxide/ADMA pathway and the improvement of oxidation resistance.

Endotoxin-induced uveitis in rodents

Uveitis is a common cause of vision loss, accounting for 10-15 % of all cases of blindness worldwide and affects individuals of all ages, genders, and races. Uveitis represents a broad range of intraocular inflammatory conditions due to complications of autoimmune diseases, bacterial infections, viral infections, and chemical and metabolic injuries. Endotoxin-induced uveitis (EIU) in rodents is an efficient experimental model to investigate the pathological mechanism and pharmacological efficacy of potential drug agents. EIU is characterized by clinically relevant classical signs of inflammation, including inflammatory exudates and cells in the anterior and vitreous chambers. EIU in small animal models such as rats, mice, and rabbits is a short-lived uveal inflammation that can be developed subsequent to administration of bacterial endotoxin, such as lipopolysaccharide. Here, we present a reproducible, reliable, and simplified protocol to induce EIU in mice. This method could be used with similar efficacy for EIU induction in other small animals as well.

The aldosterone-mineralocorticoid receptor pathway exerts anti-inflammatory effects in endotoxin-induced uveitis

We have previously shown that the eye is a mineralocorticoid-sensitive organ and we now question the role of mineralocorticoid receptor (MR) in ocular inflammation. The endotoxin-induced uveitis (EIU), a rat model of human intraocular inflammation, was induced by systemic administration of lipopolysaccharide (LPS). Evaluations were made 6 and 24 hours after intraocular injection of aldosterone (simultaneous to LPS injection). Three hours after onset of EIU, the MR and the glucocorticoid metabolizing enzyme 11-beta hydroxysteroid dehydrogenase type 2 (11β-HSD2) expression were down-regulated in iris/ciliary body and the corticosterone concentration was increased in aqueous humor, altering the normal MR/glucocorticoid receptor (GR) balance. At 24 hours, the GR expression was also decreased. In EIU, aldosterone reduced the intensity of clinical inflammation in a dose-dependent manner. The clinical benefit of aldosterone was abrogated in the presence of the MR antagonist (RU26752) and only partially with the GR antagonist (RU38486). Aldosterone reduced the release of inflammatory mediators (6 and 24 hours: TNF-α, IFN-γ, MIP-1α) in aqueous humor and the number of activated microglia/macrophages. Aldosterone partly prevented the uveitis-induced MR down-regulation. These results suggest that MR expression and activation in iris/ciliary body could protect the ocular structures against damages induced by EIU.

Management of immune-related adverse events and kinetics of response with ipilimumab

Monoclonal antibodies directed against the immune checkpoint protein cytotoxic T-lymphocyte antigen-4 (CTLA-4; CD152)-ipilimumab and tremelimumab-have been investigated in metastatic melanoma and other cancers and have shown promising results. Recently, ipilimumab was approved by the US Food and Drug Administration for the treatment of metastatic melanoma. We review the literature on managing the adverse effects and kinetics of tumor regression with ipilimumab and provide guidelines on their management. During treatment with these antibodies, a unique set of adverse effects may occur, called immune-related adverse events (irAEs). These include rashes, which may rarely progress to life-threatening toxic epidermal necrolysis, and colitis, characterized by a mild to moderate, but occasionally also severe and persistent diarrhea. Hypophysitis, hepatitis, pancreatitis, iridocyclitis, lymphadenopathy, neuropathies, and nephritis have also been reported with ipilimumab. Early recognition of irAEs and initiation of treatment are critical to reduce the risk of sequelae. Interestingly, irAEs correlated with treatment response in some studies. Unique kinetics of response have been observed with CTLA-4 blockade with at least four patterns: (1) response in baseline lesions by week 12, with no new lesions seen; (2) stable disease, followed by a slow, steady decline in total tumor burden; (3) regression of tumor after initial increase in total tumor burden; and (4) reduction in total tumor burden during or after the appearance of new lesion(s) after week 12. We provide a detailed description of irAEs and recommendations for practicing oncologists who are managing them, along with the unusual kinetics of response associated with ipilimumab therapy.

The effect of toll-like receptor 4 on macrophage cytokines during endotoxin induced uveitis

Toll-like receptor 4 (TLR4) signal activation of macrophages can lead to endotoxin-induced uveitis (EIU). Previously, our research group has demonstrated a higher expression of TLR4 in vivo during EIU than normal. In this study, we analyzed levels of peritoneal macrophage cytokines from C3H/HeN mice with LPS stimulation in vitro to elucidate the effect of TLR4 on cytokines during EIU.

[Zoledronic acid-based uveitis: a case report and a bibliography review]

There are several treatment options for postmenopausic patients suffering from ostopenia or osteoporosis; one of them being inhibition of bone resorption using bisphosphonates. The most common side effects of these drugs are of gastrointestinal nature. There are, of course, other side effects that could jeopardize the function and integrity of other organs or systems. A case of a 58-year-old patient presenting zoledronic-acid induced uveitis symptoms is reported. The importance of this paper lies in that this complication is rather exceptional, in particular if associated with the biphosphonate in question.

The NLRP3 inflammasome is active but not essential in endotoxin-induced uveitis

OBJECTIVE

The inflammasome complex involving caspase-1 and nucleotide-binding domain, leucine-rich repeat containing protein (NLRP)3, also known as NALP3 or cryopyrin is important for host responses to microbial pathogens and several autoinflammatory diseases. We investigated the extent to which NLRP3 and caspase-1 control ocular interleukin (IL)-1β production and severity of uveitis (intraocular inflammatory disease) in an established, acute inflammatory uveitis model, endotoxin-induced uveitis (EIU).

METHODS

Expression of NLRP3, its adaptor molecule ASC, also known as PYCARD (PYD and CARD domain containing), and caspase-1 were examined by immunoblotting. IL-1β production was measured by enzyme-linked immunosorbent assay (ELISA). Using knockout mice, roles for caspase-1 and NLRP3 were examined in uveitis induced by intraocular injection of Escherichia coli lipopolysaccharide (LPS).

RESULTS

NLRP3, ASC, and caspase-1 proteins are constitutively expressed in eye tissue. During EIU, IL-1β protein production increases; this requires the presence of both caspase-1 and NLRP3. However, severity of EIU is not altered by deficiency in either caspase-1 or NLRP3, as assessed by both intravital microscopy and histology.

CONCLUSIONS

These data identify the importance of the NLRP3 inflammasome for IL-1β production in the eye, yet indicate that its participation in EIU is nonessential.

Therapeutic benefit of melatonin in experimental feline uveitis

Uveitis is a frequent ophthalmic disorder which constitutes one of the main causes of blindness in domestic cats. The aim of this report was to analyze the effect of melatonin on experimentally induced uveitis in cats. Bacterial lipopolysaccharide (LPS) was injected intravitreally into one eye from intact cats, while the contralateral eye was injected with vehicle. Melatonin was orally administered every 24 hr to a group of ten cats, from 24 hr before until 45 days after intravitreal injections. Eyes were evaluated by means of clinical evaluation, intraocular pressure (IOP), blood-ocular barrier integrity (via measurement of protein concentration and cell content in samples of aqueous humor [AH]), electroretinogram (ERG), and histological examination of the retinas. In LPS-treated eyes, several clinical signs were observed until day 45 postinjection. The treatment with melatonin significantly decreased clinical signs and prevented the reduction in IOP induced by LPS. In LPS-injected eyes, melatonin significantly preserved the blood-ocular barrier integrity, as shown by a decrease in the number of infiltrating cells and protein concentration in the AH. Mean amplitudes of scotopic ERG a- and b-waves were significantly reduced in eyes injected with LPS, whereas melatonin significantly prevented the effect of LPS. At 45 days after injection, LPS induced alterations in photoreceptors and at the middle portion of the retina, whereas melatonin preserved the retinal structure. These results indicate that melatonin prevented clinical, biochemical, functional, and histological alterations induced by LPS injection. Thus, melatonin might constitute a useful tool for the treatment of feline uveitis.

A novel peptide derived from human pancreatitis-associated protein inhibits inflammation in vivo and in vitro and blocks NF-kappa B signaling pathway

Background

Pancreatitis-associated protein (PAP) is a pancreatic secretory protein belongs to the group VII of C-type lectin family. Emerging evidence suggests that PAP plays a protective effect in inflammatory diseases. In the present study, we newly identified a 16-amino-acid peptide (named PAPep) derived from C-type lectin-like domain (CTLD) of human PAP with potent anti-inflammatory activity using both in vivo and in vitro assays.

Methodology/Principal Findings

We assessed the anti-inflammatory effect of PAPep on endotoxin-induced uveitis (EIU) in rats and demonstrated that intravitreal pretreatment of PAPep concentration-dependently attenuated clinical manifestation of EIU rats, reduced protein leakage and cell infiltration into the aqueous humor (AqH), suppressed tumor necrosis factor (TNF)-α, interleukin (IL)-6, intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein (MCP)-1 production in ocular tissues, and improved histopathologic manifestation of EIU. Furthermore, PAPep suppressed the LPS-induced mRNA expression of TNF-α and IL-6 in RAW 264.7 cells, inhibited protein expression of ICAM-1 in TNF-α-stimulated human umbilical vein endothelial cells (HUVECs) as well as U937 cells adhesion to HUVECs. Western blot analysis in ocular tissues and different cell lines revealed that the possible mechanism for this anti-inflammatory effect of PAPep may depend on its ability to inhibit the activation of NF-kB signaling pathway.

Conclusions/Significance

Our studies provide the first evidence that the sequence of PAPep is within the critically active region for the anti-inflammatory function of PAP and the peptide may be a promising candidate for the management of ocular inflammatory diseases.