OBJECTIVETo gain insight into the potential mechanism of mitochondria dysfunction in pathogenesis, progression and therapeutic management of glaucoma.

DATA SOURCESThe data used in this review were mainly published in English from 2000 to present obtained from PubMed. The search terms were "mitochondria", "glaucoma" and "trabecular meshwork" or "retinal ganglion cells".

STUDY SELECTIONArticles studying the mitochondria-related pathologic mechanism and treatment of glaucoma were selected and reviewed.

RESULTSMitochondrial dysfunction or injury was demonstrated in different eye tissue of glaucoma. A variety of potential injuries (light, toxic materials, oxidative injury, mechanical stress, aging, etc.) and the inherent DNA defects are deemed to cause mitochondrial structural and functional destruction in trabecular meshwork cells, retinal ganglion cells, etc. of glaucoma. In addition, various new experimental and therapeutic interventions were used to preserve mitochondrial function, which may be useful for protecting against optic nerve degeneration or reducing the death of retinal ganglion cells in glaucoma.

CONCLUSIONSMitochondria play an important role in the pathogenesis of glaucoma, various strategies targeting mitochondrial protection might provide a promising way to delay the onset of glaucoma or protect RGCs against glaucomatous damage.

Glaucoma ; metabolism ; pathology ; Humans ; Mitochondria ; metabolism ; Retinal Ganglion Cells ; metabolism ; Trabecular Meshwork ; metabolism

PURPOSE: To investigate the effect of advanced glycation end products (AGE) on oxidative stress and cellular senescence in cultured human trabecular meshwork cells (HTMC). METHODS: Primarily cultured HTMC were exposed to 0, 10, 50, 100, 200 microg/mL of glycated bovine serum albumin (G-BSA) for 5 days. Also co-exposed were L-arginine, sepiapterin, and antioxidant N-acetylcysteine (NAC). Cellular survival and production of nitric oxide (NO), superoxide, and reactive oxygen species were assessed by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay, Griess assay, cytochrome c assay, and dichlorofluorescin diacetate assay, respectively. Senescence-associated beta-galactosidase staining was performed to quantify the degree of cellular senescence. RESULTS: G-BSA decreased cellular survival, NO production, and increased superoxide production significantly in a dose-dependent manner. The effects of G-BSA were abolished with co-exposure of L-arginine, sepiapterin, and NAC. G-BSA enhanced cellular senescence accompanied by increased production of reactive oxygen species. G-BSA-induced cellular senescence was suppressed by application of L-arginine, sepiapterin, and NAC. CONCLUSIONS: AGE enhances cellular senescence of HTMC accompanied with increased oxidative stress. AGE-induced oxidative stress and cellular senescence could be delayed by application of anti-oxidants.
Acetylcysteine/metabolism ; Apoptosis/drug effects/physiology ; Arginine/metabolism ; Cell Aging/drug effects/*physiology ; Cell Survival/drug effects/physiology ; Cells, Cultured ; Glycosylation End Products, Advanced/metabolism/*toxicity ; Humans ; Nitric Oxide/metabolism ; Oxidative Stress/*physiology ; Pterins/metabolism ; Reactive Oxygen Species/metabolism ; Serum Albumin, Bovine/metabolism/toxicity ; Trabecular Meshwork/drug effects/*metabolism/*pathology

BACKGROUNDThe role played by the nitric oxide (NO) signaling pathway in the aqueous humor dynamics is still unclear. This study was designed to investigate the expression and distribution of NO synthase (NOS) isoforms and guanylate cyclase (GC) in human ciliary body, trabecular meshwork and the Schlemm's canal.

METHODSTwelve eyes after corneal transplantation were used. Expression of three NOS isoforms (i.e. neuronal NOS (nNOS), inducible NOS (iNOS) and endothelial NOS (eNOS)) and GC were assessed in 10 eyes by immunohistochemical staining using monoclonal or polyclonal antibody of NOS and GC. Ciliary bodies were dissected free and the total proteins were extracted. Western blotting was performed to confirm the protein expression of 3 NOS isoforms and GC.

RESULTSExpression of 3 NOS isoforms and GC were observed in the ciliary epithelium, ciliary muscle, trabecular meshwork and the endothelium of the Schlemm's canal. Immunoreactivity of nNOS was detected mainly along the apical cytoplasmic junction of the non-pigmented epithelium (NPE) and pigmented epithelial (PE) cells. Protein expressions of 3 NOS isoforms and GC were confirmed in isolated human ciliary body by Western blotting.

CONCLUSIONSThe expression of NOS isoforms and GC in human ciliary body suggest the possible involvement of NO and cyclic guanosine monophosphate (cyclic GMP, cGMP) signaling pathway in the ciliary body, and may play a role in both processes of aqueous humor formation and drainage.

Ciliary Body ; enzymology ; Guanylate Cyclase ; metabolism ; Humans ; Nitric Oxide Synthase ; metabolism ; Trabecular Meshwork ; enzymology

OBJECTIVETo investigate the effects of oxidative stress on the expression of endothelialleukocyte adhesion molecule-1 (ELAM-1) in porcine trabecular meshwork cells and to elucidate the relationship between the expression of ELAM-1 and IL-1alpha.

METHODSPrimary cultured porcine trabecular meshwork cells were cultured without serum and treated with 1 mmol/L H2O2 with or without pretreatment of IL-1ralpha of different concentrations. The expression of ELAM-1 was tested by immunocytochemistry.

RESULTSELAM-1 immunocytochemistry staining was positive in the H2O2-treated porcine trabecular meshwork cells. It was negative in the porcine trabecular meshwork cells pretreated with IL-1alpha of high concentrations (180 microg/ml and 600 microg/ml).

CONCLUSIONSOxidative stress can induce the expression of ELAM-1 in porcine trabecular meshwork cells. In the in vitro cell system, IL-1ralpha of high concentration can inhibit the expression of ELAM-1 induced by oxidative stress.

Animals ; Cells, Cultured ; E-Selectin ; biosynthesis ; Hydrogen Peroxide ; pharmacology ; Interleukin 1 Receptor Antagonist Protein ; pharmacology ; Oxidative Stress ; Swine ; Trabecular Meshwork ; metabolism

PURPOSE: To investigate the effect of insulin on the production of nitric oxide (NO) in the trabecular meshwork (TM) cells and the enzymatic synthetic pathway of tetrahydrobiopterin (BH4) synthesis. METHODS: Primarily cultured human TM cells were exposed to 1, 10, and 100 microgram/ml of insulin and 0, 1, 10, 100 and 1000 nM dexamethasone for 3 days. To evaluate the enzymatic pathway of BH4 synthesis, 10 micrometer dexamethasone, 5 mM diaminopyrimidinone, 100 micrometer ascorbic acid, 100 micrometer sepiapterin, or 10 micrometer methotrexate were also co-administered respectively. Cellular survival and NO production were measured with MTT and Griess assay. RESULTS: Insulin enhanced NO production in a dose-dependent manner significantly (p<0.05) without affecting cell viability, whereas dexamethasone inhibited NO production. With co-exposure of insulin, diaminopyrimidinone and sepiapterin inhibited insulin-induced NO production. Ascorbic acid increased NO production independent of insulin and methotrexate did not affect to the action of insulin in NO production. CONCLUSIONS: Insulin increases NO production in TM cells via de novo synthetic pathway for BH4 synthesis. Insulin could be involved in the regulation of trabecular outflow by enhancing NO production in TM cells.
Trabecular Meshwork/cytology/*drug effects/*metabolism/physiology ; Nitric Oxide/*biosynthesis ; Insulin/administration & dosage/*pharmacology ; Humans ; Dose-Response Relationship, Drug ; Cells, Cultured ; Cell Survival/drug effects ; Biopterin/*analogs & derivatives/biosynthesis

PURPOSE: This study investigated the role of ascorbic acid on the production of nitric oxide (NO) in the trabecular meshwork (TM) cells. METHODS: After primarily cultured human TM cells were exposed to 1, 10, and 100 micrometer of L-ascorbic acid (LAA), with or without co-administration of 1 mM sodium nitroprusside or 100 micrometer hydrogen peroxide for 48 hr, cellular survival and NO production were measured with MTT and Griess assay, respectively. RESULTS: LAA significantly potentiated NO production in a dose-dependent manner (p< 0.05) without affecting cell viability. LAA increased cell viability after hydrogen peroxide-induced oxidative stress in a dose-dependent manner. LAA enhanced NO production in TM cells and showed a cytoprotective effect against hydrogen peroxide-induced oxidative stress. CONCLUSIONS: LAA might be involved in the regulation of trabecular outflow by enhancing NO production in TM cells.
Trabecular Meshwork/cytology/*drug effects/*metabolism ; Nitric Oxide/*biosynthesis ; Humans ; Dose-Response Relationship, Drug ; Cells, Cultured ; Cell Survival/drug effects ; Ascorbic Acid/administration & dosage/*pharmacology

Cells, Cultured ; Claudin-1 ; Dexamethasone ; pharmacology ; Electric Impedance ; Gene Expression Regulation ; drug effects ; Glaucoma ; chemically induced ; Humans ; Membrane Proteins ; genetics ; Trabecular Meshwork ; cytology ; drug effects ; metabolism

To study the effect of tTG fully phosphorothioated antisense oligodeoxynucleotides (tTG-ASDON) on tTG expression in cultured bovine trabecular meshwork cells (BTMCs) in vitro and explore a new treatment alternative for primary open angle glaucoma (POAG), the ASDON1 and ASDON2 complementary to the protein codogram region of tTG were designed, synthesized and phosphorothioated according to the secondary structure of tTG. The ASDON1 and ASDON2 were embedded in Lipofectamine and transfected into BTMCs. The untreated group served as negative controls. The expression of tTG in the mRNA and protein level were measured by semi-quantitative RT-PCR and immunohistochemical technique-Supervision method respectively. Our results showed that both the mRNA and the protein of tTG with tTG-ASDON and tTG-ASDON2 were significantly decreased as compared with that of the controls (P < 0.05). On the other hand, no significant difference was found between the ASDON1 group and the ASDON2 group. It is concluded that the expression of tTG mRNA and protein in cultured BTMC are down-regulated by tTG- ASDON. As a result, tTG-ASDON may be used for the treatment of POAG through the inhibitory effect on the expression of tTG.
Cells, Cultured ; Glaucoma, Open-Angle/metabolism ; Oligonucleotides, Antisense/*pharmacology ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Trabecular Meshwork/cytology ; Trabecular Meshwork/*metabolism ; Transglutaminases/*biosynthesis ; Transglutaminases/genetics ; Transglutaminases/*pharmacology

To evaluate the effect of dexamethasone on the expression of aquaporin-1 (AQP-1) in cultured bovine trabecular meshwork cells, bovine trabecular meshwork cells were cultured in vitro and reproduced to the third and the fourth generation, then treated with dexamethasone at the concentrations of 5, 25, 50, 250 microg/L respectively for 7 days. Immunohistochemical technique-supervision method was employed to measure, and image analysis system to analyze the expression of AQP-1 in normal cultured bovine trabecular meshwork cells and those treated with dexamethasone. In normal bovine trabecular meshwork cells, the grayscale of AQP-1 positive staining was 167.94 +/- 1.18, while it was 168.92 +/- 0.91, 176.72 +/- 1.80, 180.64 +/- 1.31, 185.64 +/- 1.58 in cells treated with 5, 25, 50, 250 microg/L concentrations of dexamethasone. When the concentration of dexamethasone was higher than 25 microg/L, the expression of AQP-1 was significantly inhibited (P < 0.05). The regulation of AQP-1 expression by dexamethasone in cultured bovine trabecular meshwork cells in vitro may be one of causes that retard the aqueous outflow in glucocorticoid- induced glaucoma.
Aquaporin 1/*biosynthesis ; Aquaporin 1/genetics ; Cells, Cultured ; Depression, Chemical ; Dexamethasone/*pharmacology ; Dose-Response Relationship, Drug ; Immunohistochemistry ; Trabecular Meshwork/cytology ; Trabecular Meshwork/*metabolism

To confirm the existence of heme oxygenase (HO)- carbon monoxide (CO)- cyclic guanosine monophosphate (cGMP) pathway in the cultured human trabecular meshwork cells (HT-MCs) in vitro, and to evaluate the inductive role of hemin on this pathway, HTMCs of the third to fourth generation were cultured in vitro. Reverse transcripase-polymerase chain reaction (RT-PCR) was employed for detection of HO-1 and HO-2 mRNA. Immunohistochemical staining was used to detect HO-1 and HO-2 proteins. Hemin was added into the culture solution. The HO-1 mRNA levels were quantified by RT-PCR. The relative amount of carbon monoxide released into the media was measured with the quantifying carbon monoxide hemoglobin (HbCO) by spectrophotometry. Radioimmunoassay was used to determine changes of cGMP in HTMCs. The results showed that cultured cells had the specific characteristics of HTMCs. Both HO-1 and HO-2 genes were expressed in HTMCs, as well as HO-1 and HO-2 proteins in HTMCs. Hemin induced HO-1 mRNA, HbCO and cGMP in a dose-dependent manner. In conclusion, HO-CO-cGMP pathway exists in the cultured HTMCs and can be induced by hemin. Pharmacological stimulation of HO-CO-cGMP pathway may constitute a novel therapeutic approach to rescuing glaucoma.
Carbon Monoxide ; metabolism ; Cells, Cultured ; Cyclic GMP ; biosynthesis ; genetics ; Heme Oxygenase (Decyclizing) ; biosynthesis ; genetics ; Humans ; RNA, Messenger ; biosynthesis ; genetics ; Signal Transduction ; Trabecular Meshwork ; cytology ; metabolism