11-cis-retinal and Inflammation

Patients with diabetes often experience visual defects before any retinal pathologies are detected. The molecular mechanism for the visual defects in early diabetes has not been elucidated. Our previous study reported that in early diabetic retinopathy (DR), rhodopsin levels were reduced due to impaired 11-

Topics: Animals; Apoptosis; Blotting, Western; Diabetic Retinopathy; Eye Proteins; Immunohistochemistry; In Situ Nick-End Labeling; Inflammation; Mice; Mice, Transgenic; Oxidative Stress; Retinal Degeneration; Retinol-Binding Proteins; Rhodopsin; Tomography, Optical Coherence

In retinitis pigmentosa (RP), one of many possible genetic mutations causes rod degeneration, followed by cone secondary death leading to blindness. Accumulating evidence indicates that rod death triggers multiple, non-cell-autonomous processes, which include oxidative stress and inflammation/immune responses, all contributing to cone demise. Inflammation relies on local microglia and recruitment of immune cells, reaching the retina through breakdowns of the inner blood retinal barrier (iBRB). Leakage in the inner retina vasculature suggests similarly altered outer BRB, formed by junctions between retinal pigment epithelium (RPE) cells, which are crucial for retinal homeostasis, immune response, and privilege. We investigated the RPE structural integrity in three models of RP (rd9, rd10, and Tvrm4 mice) by immunostaining for zonula occludens-1 (ZO-1), an essential regulatory component of tight junctions. Quantitative image analysis demonstrated discontinuities in ZO-1 profiles in all mutants, despite different degrees of photoreceptor loss. ZO-1 interruption zones corresponded to leakage of in vivo administered, fluorescent dextran through the choroid-RPE interface, demonstrating barrier dysfunction. Dexamethasone, administered to rd10 mice for rescuing cones, also rescued RPE structure. Thus, previously undetected, stereotyped abnormalities occur in the RPE of RP mice; pharmacological targeting of inflammation supports a feedback loop leading to simultaneous protection of cones and the RPE.

Topics: Animals; Dexamethasone; Disease Models, Animal; Evaluation Studies as Topic; Inflammation; Mice; Mice, Inbred C57BL; Retina; Retinal Cone Photoreceptor Cells; Retinal Pigment Epithelium; Retinal Rod Photoreceptor Cells; Retinal Vessels; Retinitis Pigmentosa; Rhodopsin; Tight Junctions; Zonula Occludens-1 Protein

We previously reported that modest running exercise protects photoreceptors in mice undergoing light-induced retinal degeneration and in the rd10 mouse model of autosomal recessive retinitis pigmentosa (arRP). We hypothesized that exercise would protect against other types of retinal degeneration, specifically, in autosomal dominant inherited disease. We tested whether voluntary running wheel exercise is protective in a retinal degeneration mouse model of class B1 autosomal dominant RP (adRP).. C57BL/6J mice heterozygous for the mutation in I307N rhodopsin (. In vivo measures revealed that induction of the I307N. Voluntary wheel running partially protected against retinal degeneration and inflammation, and RPE disruption in a model of inducible adRP. This is the first report of exercise protection in an adult adRP animal model. It is also the first report of an RPE phenotype in the I307N

Topics: Animals; Disease Models, Animal; Genes, Dominant; Inflammation; Mice, Inbred C57BL; Mutation; Photoreceptor Cells, Vertebrate; Physical Conditioning, Animal; Retinal Degeneration; Retinal Pigment Epithelium; Retinitis Pigmentosa; Rhodopsin; Vision, Ocular

Topics: Animals; Cell Death; cis-trans-Isomerases; Digoxin; Eye Proteins; Inflammation; Light; Mice; Mice, Inbred C57BL; Mice, Knockout; Retina; Retinal Cone Photoreceptor Cells; Retinal Degeneration; Retinal Rod Photoreceptor Cells; Rhodopsin; Signal Transduction; Sodium-Potassium-Exchanging ATPase; Stress, Physiological; Vision, Ocular

Compelling evidence suggests that transplantation of neural stem cells (NSCs) from multiple sources ameliorates motor deficits after stroke. However, it is currently unknown to what extent the electrophysiological activity of grafted NSC progeny participates in the improvement of motor deficits and whether excitatory phenotypes of the grafted cells are beneficial or deleterious to sensorimotor performances. To address this question, we used optogenetic tools to drive the excitatory outputs of the grafted NSCs and assess the impact on local circuitry and sensorimotor performance. We genetically engineered NSCs to express the Channelrhodopsin-2 (ChR2), a light-gated cation channel that evokes neuronal depolarization and initiation of action potentials with precise temporal control to light stimulation. To test the function of these cells in a stroke model, rats were subjected to an ischemic stroke and grafted with ChR2-NSCs. The grafted NSCs identified with a human-specific nuclear marker survived in the peri-infarct tissue and coexpressed the ChR2 transgene with the neuronal markers TuJ1 and NeuN. Gene expression analysis in stimulated versus vehicle-treated animals showed a differential upregulation of transcripts involved in neurotransmission, neuronal differentiation, regeneration, axonal guidance, and synaptic plasticity. Interestingly, genes involved in the inflammatory response were significantly downregulated. Behavioral analysis demonstrated that chronic optogenetic stimulation of the ChR2-NSCs enhanced forelimb use on the stroke-affected side and motor activity in an open field test. Together these data suggest that excitatory stimulation of grafted NSCs elicits beneficial effects in experimental stroke model through cell replacement and non-cell replacement, anti-inflammatory/neurotrophic effects.

Topics: Animals; Cell Separation; Disease Models, Animal; Down-Regulation; Gene Expression Profiling; Human Embryonic Stem Cells; Humans; Inflammation; Male; Neostriatum; Neural Stem Cells; Oligonucleotide Array Sequence Analysis; Optogenetics; Rats, Sprague-Dawley; Rhodopsin; Stroke; Synaptic Transmission; Transduction, Genetic; Transgenes

Photoreceptor death leads to vision impairment in several retinal degenerative disorders. Therapies protecting photoreceptor from degeneration remain to be developed. Anti-inflammation, anti-oxidative stress, and neuroprotective effects of celastrol have been demonstrated in a variety of disease models. The current study aimed to investigate the photoreceptor protective effect of celastrol.. Bright light-induced retinal degeneration in BALB/c mice was used, and morphological, functional, and molecular changes of retina were evaluated in the absence and presence of celastrol treatment.. Significant morphological and functional protection was observed as a result of celastrol treatment in bright light-exposed BALB/c mice. Celastrol treatment resulted in suppression of cell death in photoreceptor cells, alleviation of oxidative stress in the retinal pigment epithelium and photoreceptors, downregulation of retinal expression of proinflammatory genes, and suppression of microglia activation and gliosis in the retina. Additionally, leukostasis was found to be induced in the retinal vasculature in light-exposed BALB/c mice, which was significantly attenuated by celastrol treatment. In vitro, celastrol attenuated all-trans-retinal-induced oxidative stress in cultured APRE19 cells. Moreover, celastrol treatment significantly suppressed lipopolysaccharides-stimulated expression of proinflammatory genes in both APRE19 and RAW264.7 cells.. The results demonstrated for the first time that celastrol prevents against light-induced retinal degeneration through inhibition of retinal oxidative stress and inflammation.

Topics: Animals; Cells, Cultured; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Female; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Inflammation; Light; Lipopolysaccharides; Mice; Mice, Inbred BALB C; Neuroprotective Agents; Opsins; Oxidative Stress; Pentacyclic Triterpenes; Retinal Degeneration; Rhodopsin; Triterpenes

An unfolded protein response (UPR) in addition to oxidative stress and the inflammatory response is known to be activated in age-related ocular disorders, such as macular degeneration, diabetic retinopathy, glaucoma, and cataracts. Therefore, we aimed to investigate whether healthy aged retinas display UPR hallmarks, in order to establish a baseline for the activated UPR markers for age-related ocular diseases. Using western blotting, we determined that the hallmarks of the UPR PERK arm, phosphorylated (p) eIF2a, ATF4, and GADD34, were significantly altered in aged vs. young rat retinas. The cleaved pATF6 (50) and CHOP proteins were dramatically upregulated in the aged rodent retinas, indicating the activation of the ATF6 UPR arm. The UPR activation was associated with a drop in rhodopsin expression and in the NRF2 and HO1 levels, suggesting a decline in the anti-oxidant defense in aged retinas. Moreover, we observed down-regulation of anti-inflammatory IL-10 and IL-13 and upregulation of pro-inflammatory RANTES in the healthy aged retinas, as measured using the Bio-plex assay. Our results suggest that cellular homeostasis in normal aged retinas is compromised, resulting in the concomitant activation of the UPR, oxidative stress, and inflammatory signaling. This knowledge brings us closer to understanding the cellular mechanisms of the age-related retinopathies and ocular disorders characterized by an ongoing UPR, and highlight the UPR signaling molecules that should be validated as potential therapeutic targets.

Topics: Aging; Animals; Biomarkers; Inflammation; Mice, Inbred C57BL; Oxidative Stress; Rats, Inbred F344; Retina; Rhodopsin; Unfolded Protein Response

Neurons in the anterior cingulate cortex (ACC) are assumed to play important roles in the perception of nociceptive signals and the associated emotional responses. However, the neuronal types within the ACC that mediate these functions are poorly understood. In the present study, we used optogenetic techniques to selectively modulate excitatory pyramidal neurons and inhibitory interneurons in the ACC and to assess their ability to modulate peripheral mechanical hypersensitivity in freely moving mice. We found that selective activation of pyramidal neurons rapidly and acutely reduced nociceptive thresholds and that this effect was occluded in animals made hypersensitive using Freund's Complete Adjuvant (CFA). Conversely, inhibition of ACC pyramidal neurons rapidly and acutely reduced hypersensitivity induced by CFA treatment. A similar analgesic effect was induced by activation of parvalbumin (PV) expressing interneurons, whereas activation of somatostatin (SOM) expressing interneurons had no effect on pain thresholds. Our results provide direct evidence of the pivotal role of ACC excitatory neurons, and their regulation by PV expressing interneurons, in nociception.

Topics: Animals; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Chronic Pain; Freund's Adjuvant; Gyrus Cinguli; Hyperalgesia; Inflammation; Integrases; Interneurons; Male; Mice; Neural Inhibition; Neurons; Optogenetics; Pain Threshold; Parvalbumins; Rhodopsin

Recent progress in molecular analysis has revealed the possible involvement of multiple inflammatory signaling pathways in pathogenesis of retinal degeneration. However, how aberrant signaling pathways cause tissue damage and dysfunction is still being elucidated. Here, we focus on 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK), originally recognized as a key regulator of energy homeostasis. AMPK is also modulated in response to inflammatory signals, although its functions in inflamed tissue are obscure. We investigated the role of activated AMPK in the retinal neural damage and visual function impairment caused by inflammation. For this purpose, we used a mouse model of lipopolysaccharide-induced inflammation in the retina, and examined the effects of an AMPK activator, 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR). During inflammation, activated AMPK in the neural retina was decreased, but AICAR treatment prevented this change. Moreover, the electroretinogram (ERG) a-wave response, representing photoreceptor function, showed visual dysfunction in this model that was prevented by AICAR. Consistently, the model showed shortened photoreceptor outer segments (OSs) with reduced levels of rhodopsin, a visual pigment concentrated in the OSs, in a post-transcriptional manner, and these effects were also prevented by AICAR. In parallel, the level of activated NF-κB increased in the retina during inflammation, and this increase was suppressed by AICAR. Treatment with an NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ) preserved the rhodopsin level during inflammation, suppressing NF-κB. These findings indicated that AMPK activation by AICAR and subsequent NF-κB inhibition had a protective effect on visual function, and that AMPK activation played a neuroprotective role during retinal inflammation.

Topics: Adenylate Kinase; Aminoimidazole Carboxamide; Animals; Electroretinography; Inflammation; Male; Mice; NF-kappa B; Photoreceptor Cells; Retinal Diseases; Rhodopsin; Ribonucleotides; Signal Transduction

CCR3, a G protein-coupled receptor, plays a central role in allergic inflammation and is an important drug target for inflammatory diseases. To understand the structure-function relationship of CCR3 receptor, different computational techniques were employed, which mainly include: (i) homology modeling of CCR3 receptor, (ii) 3D-quantitative pharmacophore model of CCR3 antagonists, (iii) virtual screening of small compound databases, and (iv) finally, molecular docking at the binding site of the CCR3 receptor homology model. Pharmacophore model was developed for the first time, on a training data set of 22 CCR3 antagonists, using CATALYST HypoRefine program. Best hypothesis (Hypo1) has three different chemical features: two hydrogen-bond acceptors, one hydrophobic, and one ring aromatic. Hypo1 model was further validated using (i) 87 test set CCR3 antagonists, (ii) Cat Scramble randomization technique, and (iii) Decoy data set. Molecular docking studies were performed on modeled CCR3 receptor using 303 virtually screened hits, obtained from small compound database virtual screening. Finally, five hits were identified as potential leads against CCR3 receptor, which exhibited good estimated activities, favorable binding interactions, and high docking scores. These studies provided useful information on the structurally vital residues of CCR3 receptor involved in the antagonist binding, and their unexplored potential for the future development of potent CCR3 receptor antagonists.

Topics: Amino Acid Sequence; Animals; Binding Sites; Cattle; Chemokine CCL11; CHO Cells; Cricetinae; Cricetulus; Databases, Factual; High-Throughput Screening Assays; Humans; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Hypersensitivity; Inflammation; Models, Molecular; Molecular Dynamics Simulation; Molecular Sequence Data; Protein Binding; Receptors, CCR3; Rhodopsin; Sequence Alignment; Small Molecule Libraries; Structure-Activity Relationship

Our previous studies have shown that very low-density lipoprotein receptor (VLDLR) is a negative regulator of the Wnt pathway. The present study showed that VLDLR gene knockout (Vldlr(-/-)) mice displayed impaired cone ERG responses at early ages. Immunostaining of mid-wavelength cones showed significantly decreased cone densities in the retina and shortened cone outer segments in Vldlr(-/-) mice. At older ages, Vldlr(-/-) mice displayed declined rod ERG responses, decreased layers of photoreceptor nuclei, reduced rhodopsin levels and decreased levels of 11-cis retinal, the chromophore of visual pigments. As shown by fluorescein angiography and permeability assay, Vldlr(-/-) mice had severe retinal vascular leakage. ZO-1, a tight junction protein, was down-regulated in Vldlr(-/-) mouse retinae, further supporting the impaired blood-retinal barrier. Double staining of pericytes and endothelial cells in retinal sections revealed that neovasculature in Vldlr(-/-) mice lacks pericyte coverage, suggesting impaired maturation of retinal vasculature in Vldlr(-/-) mice. Staining of adherent leukocytes in the retinal vasculature revealed significant leukostasis in Vldlr(-/-) mice. Moreover, Vldlr(-/-) mice displayed up-regulated expression of multiple pro-inflammatory factors and activated NF-kappaB and HIF-1 alpha, key regulators of inflammation. These findings suggest that deficiency of VLDLR leads to retinal degeneration and inflammation.

Topics: Animals; Down-Regulation; Electroretinography; Fluorescein Angiography; Inflammation; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Phosphoproteins; Receptors, LDL; Retina; Retinal Cone Photoreceptor Cells; Retinal Rod Photoreceptor Cells; Rhodopsin; Rod Opsins; Zonula Occludens-1 Protein