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

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

A preliminary study was performed to investigate the staining characteristics of trabecula. endothelial cells with low density lipoprotein (LDL) and acetylated low density lipoprotein (Ac-LDL) labeled with a fluorescent probe, 1, 1`- dioctadecyl-3,3,3`, 3`- tetramethyl-indocarbocyanine perchlorate (Dil). Trabecular endothelial cells revealed a strong fluorescence with Dil-LDL, which was contradictory to the previous results obtained from other types of endothelial cells. These cells also showed a moderate fluorescence with Dil-Ac-LDL. Scleral fibroblasts and keratocytes showed a moderate to strong fluorescence with Dil-LDL and a weak fluorescence with Dil-Ac-LDL. Corneal endothelial cells revealed a very weak background fluorescence with Dil-LDL and a moderate fluorescence with Dil-Ar-LDL. Therefore, these four kinds of cells could not be definitely differentiated depending only on the staining characteristics with Dil-LDL and Dil-Ac-LDt.
Animals ; Cattle ; Endothelium/cytology ; Fluorescent Dyes/*diagnostic use ; Lipoproteins, LDL/*metabolism ; Trabecular Meshwork/*metabolism

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

We examined the fibronectin (FN) secretion of cultured trabecular meshwork (TM) cells in a normal human eye by indirect immunofluorescent technique using mouse anti-human FN monoclonal antibody and FITC-conjugated goat anti-mouse IgG. To localize FN on frozen sections of normal TM, which were obtained from 7 enucleated eyes owing to traumatic eyeball rupture, the same indirect immunofluorescent method was used. Immunoelectron microscopy was applied to demonstrate the distribution pattern of FN in the normal TM of 2 human eyes using an avidin-biotin-peroxidase complex method. In the tissue culture of TM, the TM cell walls and extracellular matrices showed an intense staining with antibody to FN. Indirect immunofluorescent staining of FN on frozen sections of TM showed strong positive reactions in the subendothelial region. There was no reaction in the central core of the trabecular beam. Immunoelectron microscopy revealed the reaction products to FN in the areas lining the trabecular endothelial cells.
Adolescent ; Adult ; Antibodies, Monoclonal ; Cells, Cultured ; Fibronectins/biosynthesis/*metabolism ; Fluorescent Antibody Technique ; Humans ; Male ; Microscopy, Immunoelectron ; Trabecular Meshwork/*metabolism/ultrastructure

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 ; Cyclic GMP/genetics ; Heme Oxygenase (Decyclizing)/*biosynthesis ; Heme Oxygenase (Decyclizing)/genetics ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Signal Transduction ; Trabecular Meshwork/cytology ; Trabecular Meshwork/*metabolism

The effects of suppression of CD44 by CD44-specific antisense oligonucleotide on attachment of human trabecular meshwork cells to hyaluronic acid (HA) were observed and the possible relationship between CD44 and primary open-angle glaucoma (POAG) investigated. CD44-specific antisense oligonucleotide was delivered with cationic lipid to cultured human trabecular meshwork cells. The expression of CD44 suppressed by CD44-specific antisense oligonucleotide was detected by RT-PCR and Western blotting. The effect of CD44 suppression by specific antisense oligonucleotide on attachment of trabecular meshwork cells to HA was measured by MTT assay. Results showed that expression of CD44 was suppressed by CD44-specific antisense oligonucleotide. Antisense oligonucleotide also suppressed the adhesion of human trabecular meshwork cells to HA in a concentration dependent manner. It was concluded that attachment of human trabecular meshwork cells to HA was decreased when CD44 was suppressed by specific antisense oligonucleotide. CD44 might play a role in pathogenesis of POAG by affecting the adhesion of trabecular meshwork cells to HA.
Cell Adhesion ; Cells, Cultured ; Glaucoma, Open-Angle ; metabolism ; pathology ; Humans ; Hyaluronan Receptors ; biosynthesis ; genetics ; Hyaluronic Acid ; metabolism ; Oligonucleotides, Antisense ; pharmacology ; Trabecular Meshwork ; cytology

To study whether cultured bovine trabecluar meshwork cells (BTMC) are capable of expressing tTG in protein and at mRNA level, BTMC were cultured in vitro and passaged three times, then the cells were transferred onto or cultured on sterile cover or submitted to isolation of RNA with Trizol, and the expression of tTG was detected by immunohistochemical technique and reverse transcription polymerase chain reaction (RT-PCR) respectively. Our results showed that tTG immunostaining was positive in the cytoplasm and rarely in the nucleus of cultured BTMC. No immunostaining was seen in the negative control. Moreover, a single RT-PCR amplified product whose sequence and size were in accordance with our known parameters was obtained. The expression of tTG in cultured BTMC was confirmed in protein and at mRNA level. BMTC is available more readily for the investigation of the relationship between tTG and primary open-angle glaucoma.
Cells, Cultured ; Glaucoma, Open-Angle/metabolism ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Trabecular Meshwork/*metabolism ; Transglutaminases/*biosynthesis ; Transglutaminases/genetics

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