ULTRA-WIDE FIELD FUNDUS AUTOFLUORESCENCE IMAGING OF EYES WITH STICKLER SYNDROME.

PURPOSE: To determine the characteristics of fundus autofluorescence (FAF) images and visual functions in eyes with Stickler syndrome using ultra-widefield FAF images. METHODS: Forty-six eyes of 26 patients with mutations in the COL2A1 gene underwent ultra-widefield FAF imaging. The eyes were categorized into three types; no signs of abnormal AF, predominantly hyperfluorescent AF (hyper-AF), and predominantly hypofluorescent AF (hypo-AF). Goldmann perimetry was performed on 34 eyes, and line-scan images of the abnormal AF lesions were obtained by swept-source optical coherence tomography in 4 eyes. RESULTS: Abnormal AF lesions were found in 37 eyes of 21 (80.7%) of the 26 patients. Hyper-AF was found in 15 eyes and hypo-AF was found in 22 eyes. The FAF changes corresponded with the funduscopically observed radial paravascular retinal degeneration. The average age at the examination was significantly younger in patients who had eyes with hyper-AF or no abnormal AF than in those with hypo-AF (12.8 vs. 28.4 years; P = 0.009). Abnormal AF-associated visual field defects were found in 5/10 (50%) eyes with hyper-AF and 17/18 (94%) eyes with hypo-AF. Hyper-AF changes tended to appear before retinal changes were detectable by fluorescein angiography. An absence of the ellipsoid zone and the outer nuclear layer and a thinning of the overall retinal thickness were found corresponding to the hypo-AF lesions in the swept source optical coherence tomography images. CONCLUSION: Abnormal FAF is characteristic of eyes with Stickler syndrome. Age-related alterations of the FAF was associated with visual field defects and disruption of the photoreceptors and retinal pigment epithelial cells.

Exosc2 deficiency leads to developmental disorders by causing a nucleotide pool imbalance in zebrafish.

Exosc2 is one of the components of the exosome complex involved in RNA 3' end processing and degradation of various RNAs. Recently, EXOSC2 mutation has been reported in German families presenting short stature, hearing loss, retinitis pigmentosa, and premature aging. However, the in vivo function of EXOSC2 has been elusive. Herein, we generated Exosc2 knockout (exosc2-/-) zebrafish that showed larval lethality 13 days post fertilization, with microcephaly, loss of spinal motor neurons, myelin deficiency, and retinitis pigmentosa. Mechanistically, Exosc2 deficiency caused impaired mRNA turnover, resulting in a nucleotide pool imbalance. Rapamycin, which modulated mRNA turnover by inhibiting the mTOR pathway, improved nucleotide pool imbalance in exosc2-/- zebrafish, resulting in prolonged survival and partial rescue of neuronal defects. Taken together, our findings offer new insights into the disease pathogenesis caused by Exosc2 deficiency, and might help explain fundamental molecular mechanisms in neuronal diseases, such as Alzheimer's disease, amyotrophic lateral sclerosis, and spinal muscular atrophy.

Foveal Hypoplasia in Patients with Stickler Syndrome.

PURPOSE: To determine the microstructure of the fovea in patients with Stickler syndrome using imaging by spectral-domain optical coherence tomography (SD OCT) and swept-source OCT. DESIGN: Retrospective case series study. PARTICIPANTS: A total of 39 eyes of 25 patients with genetically confirmed Stickler syndrome were studied. METHODS: All of the patients had mutations in the COL2A1 gene and were diagnosed with Stickler syndrome. Cross-sectional OCT images, OCT angiography (OCTA), and en face OCT images were assessed. The ratio of the foveal inner retinal layer (fIRL) thickness to the parafoveal inner retinal layer (pIRL) thickness, the ratio of the foveal outer retinal layer (fORL) thickness to the parafoveal outer retinal layer (pORL) thickness, and the size of the foveal avascular zone (FAZ) were determined. MAIN OUTCOME MEASURES: The degree of foveal hypoplasia and the best-corrected visual acuity in patients with Stickler syndrome. RESULTS: A persistence of the inner retinal layers in the fovea with an fIRL/pIRL ratio >0.2 was present in 32 of the 39 eyes (82%). Optical coherence tomography angiography showed that the FAZ was smaller, 0 to 0.19 mm2, than that of normal eyes, in 25 eyes of 17 patients who underwent OCTA. There was no significant correlation between the visual acuities and the fIRL/pIRL ratios. CONCLUSIONS: A mild foveal hypoplasia with a persistence of the IRL is characteristic of eyes with Stickler syndrome. The visual acuities were not correlated with the fIRL/pIRL ratios.

One-Year Outcomes following Intravitreal Aflibercept for Polypoidal Choroidal Vasculopathy in Japanese Patients: The APOLLO Study.

PURPOSE: To evaluate 1-year outcomes of intravitreal injections of aflibercept (IVA) in Japanese polypoidal choroidal vasculopathy (PCV) patients. METHODS: In this prospective, open-label, single-arm multicenter clinical trial, treatment-naïve PCV patients received IVA (2.0 mg) every 2 months, after 3 initial monthly doses. The primary endpoint assessed was the proportion of patients maintaining baseline best-corrected visual acuity (BCVA) at 1 year. RESULTS: Fifty eyes with PCV were included in the study. BCVA was maintained or improved in 97.6% of the patients. Mean logMAR BCVA at baseline was 0.33, and had improved to 0.12 logMAR 1 year after the initiation of aflibercept treatment (p < 0.001). Mean central foveal thickness decreased from 356 to 239 µm (p < 0.001). Complete regression of polypoidal lesions was seen in 72.5% after 1 year of treatment. CONCLUSIONS: One year of IVA resulted in stabilization of BCVA and anatomical improvement in Japanese PCV patients.

Mitomycin C modulates the circadian oscillation of clock gene period 2 expression through attenuating the glucocorticoid signaling in mouse fibroblasts.

Clock gene regulates the circadian rhythm of various physiological functions. The expression of clock gene has been shown to be attenuated by certain drugs, resulting in a rhythm disorder. Mitomycin C (MMC) is often used in combination with ophthalmic surgery, especially in trabeculectomy, a glaucoma surgical procedure. The purpose of this study was to investigate the influence of MMC on clock gene expression in fibroblasts, the target cells of MMC. Following MMC treatment, Bmal1 mRNA levels was significantly decreased, whereas Dbp, Per1, and Rev-erbα mRNA levels were significantly increased in the mouse fibroblast cell line NIH3T3 cells. Microarray analysis was performed to explore of the gene(s) responsible for MMC-induced alteration of clock gene expression, and identified Nr3c1 gene encoding glucocorticoid receptor (GR) as a candidate. MMC suppressed the induction of Per1 mRNA by dexamethasone (DEX), ligand of GR, in NIH3T3 cells. MMC also modulated the DEX-driven circadian oscillations of Per2::Luciferase bioluminescence in mouse-derived ocular fibroblasts. Our results demonstrate a previously unknown effect of MMC in GR signaling and the circadian clock system. The present findings suggest that MMC combined with trabeculectomy could increase the risk for a local circadian rhythm-disorder at the ocular surface.

Magnetic resonance imaging findings of high myopic strabismus with sagging eye-like symptoms, heavy eye syndrome, and non-highly myopic eyes with sagging eye syndrome.

INTRODUCTION: Progressive esotropia accompanied by restricted abduction and supraduction due to high myopia is known as esotropia fixus with high myopia or heavy eye syndrome (HES). Some conditions, such as sagging eye syndrome (SES), show esotropia for distance or cyclovertical strabismus with no abduction limitations despite highly myopic eyes. We evaluated the magnetic resonance imaging (MRI) findings and clinical features of HES, high myopia with SES-like symptoms (highly myopic SES), and SES. METHODS: We reviewed all patients diagnosed with HES, highly myopic SES, and SES who underwent MRI of the orbits and brain over 6 years. To quantitatively assess the orbital anatomy, we compared the conditions of the superior rectus muscle (SR), lateral rectus muscle (LR), and inferior rectus muscle (IR) using orbital MRI among the three groups. RESULTS: Among the 14 patients (27 eyes) with high myopia, 5 (9 eyes) had HES, and 9 (18 eyes) had highly myopic SES. Eleven patients (22 eyes) with SES were also compared with these 14 patients. The mean axial length was 29.6 ± 1.0 mm in participants with HES, 29.0 ± 1.5 mm in those with HES-SES, and 23.7 ± 0.9 mm in those with SES. The average distance esotropia was 48.0 ± 19.9Δprism, 4.6 ± 1.5Δprism, and 6.1 ± 4.6Δprism for participants with HES, highly myopic SES and SES, respectively. The average distance hypertropia was 5.3 ± 5.9Δprism in participants with highly myopic SES and 4.8 ± 2.7Δprism in those with SES. The mean vertical angle of the LR was 32.6 ± 10.8°, 18.1 ± 5.4°, and 14.6 ± 6.8°; the mean tilting angle of the LR was 31.6 ± 9.2°, 15.9 ± 6.0°, and 13.8 ± 5.9°; and the mean displacement angle between the LR and SR was 152.3 ± 16.7°, 125.0 ± 7.1°, and 112.5 ± 7.5° for participants with HES, highly myopic SES and SES, respectively. The LR-SR displacement angle in HES-SES was significantly larger than in SES (p < .001) but the vertical and tilting angles were not. Also, the IR shift showed no significant difference with HES-SES and HES (5.8 ± 1.4 mm and 5.3 ± 1.2 mm) but not with SES (4.0 ± 0.8 mm) (p < .0001). DISCUSSION: SES-like symptoms can develop in highly myopic eyes; however, MRI showed that the state of the LR muscle in highly myopic SES deviated almost similarly to that in SES; however, the eyeball was more dislocated than in SES. This may be useful in deciding the appropriate operative procedure.

Associations of Diabetic Retinopathy Severity With High Ambulatory Blood Pressure and Suppressed Serum Renin Levels.

CONTEXT: The relationships between serum renin levels, severity of diabetic retinopathy (DR), and 24-hour blood pressure (BP) have not been previously reported. OBJECTIVE: To explore causes for DR and the relationships of 24-hour ambulatory BP, and hormone levels with the severity of DR. METHODS: The diabetic patients were classified as having no DR, simple DR, or severe DR (preproliferative DR plus proliferative DR) based on funduscopic examination, and we measured 24-hour BP, serum active renin (ARC), aldosterone (SAC), adrenocorticotropic hormone, and cortisol levels in each group. RESULTS: Compared to those with no DR or simple DR, patients with severe DR showed significantly higher 24-hour BPs, including daytime and nighttime systolic and diastolic BP levels, independent of diabetic duration and HbA1c levels. The variability of nighttime systolic BP was greater in patients with severe DR than in those with nonsevere DR, although nocturnal BP reduction was similar between the groups. The ambulatory BPs were significantly inversely associated with ARC. The ARC was significantly lower in severe DR patients than in those with no DR or simple DR (3.2 [1.5-13.6] vs 9.8 [4.6-18.0] pg/mL, P < .05), but there were no differences in SAC in patients taking calcium channel blockers and/or α-blockers. No associations were found between DR severity and other hormone levels. CONCLUSION: Severe DR was associated with higher 24-hour BPs and suppressed ARC. These findings suggest that mineralocorticoid receptor overactivation may play a role in higher BP levels and severe DR in diabetic patients.

The PI3K/Akt pathway mediates the expression of type I collagen induced by TGF-ß2 in human retinal pigment epithelial cells.

PURPOSE: Transforming growth factor (TGF)-ß is a key mediator of proliferative vitreoretinopathy, but the cellular mechanisms by which TGF-ß induces extracellular matrix protein (ECM) synthesis are not fully understood. This study examined whether the PI3K/Akt pathway is involved in TGF-ß2-induced collagen expression in human retinal pigment epithelial cells. METHODS: Human retinal pigment epithelial cells ARPE-19 were cultured and stimulated with TGF-ß2. The role of the PI3K/Akt pathway was evaluated using the biochemical inhibitor, wortmannin. The effect of wortmannin on the expression of type I collagen mRNA (COL1A1, COL1A2) induced by TGF-ß2 was evaluated by real-time RT-PCR. The effect of wortmannin on the synthesis of type I collagen induced by TGF-ß2 was assessed by an immunocytochemical analysis with anti-type I collagen antibody. Luciferase reporter assays were performed to examine the effect of wortmannin on the transcriptional activities of COL1A2. A luciferase assay using a mutation construct of the Smad binding site in COL1A2 promoter (Smad-mut/Luc) was also performed to examine the crosstalk between the Smad pathway and the PI3K/Akt pathway. The effects of wortmannin on the transcriptional activity of Smad3 were also examined using CAGA12-Luc. Moreover, the effect of wortmannin on TGF-ß2-induced Smad7 mRNA expression was evaluated. RESULTS: The biochemical blockade of PI3K/Akt activation inhibited TGF-ß2-induced type I collagen mRNA expression and type I collagen synthesis. The blockade of PI3K/Akt pathway inhibited the increase in COL1A2 promoter activities when induced by TGF-ß2 and reduced TGF-ß2 induction of Smad-mut/Luc promoter activity and CAGA12-Luc activity. Moreover, wortmannin increased the TGF-ß2-induced Smad7 mRNA expression levels. CONCLUSIONS: The PI3K/Akt pathway plays a role in relaying the TGF-ß2 signal to induce type I collagen synthesis in the retinal pigment epithelium through Smad-dependent and Smad-independent pathways.

Macular neovascularisation in a patient with osteogenesis imperfecta exhibiting a novel COL1A1 mutation.

Osteogenesis imperfecta is a congenital disease that presents with varying degrees of connective tissue symptoms, including susceptibility to fracture, growth disorders and hearing loss. Here, we discuss a case in which macular neovascularisation (MNV) resulted in metamorphopsia and decreased visual acuity in a patient with osteogenesis imperfecta exhibiting a novel COL1A1 gene mutation (p.Tyr165*). The patient was a woman in her 30s who reported experiencing distorted vision and diminished visual acuity in her right eye for 1 month as well as a history of hearing loss. Rapid improvements in exudative changes and suppression of relapse were achieved after only two intravitreal injections of ranibizumab. Furthermore, since MNV occurred slightly inferior to the fovea centralis, improvements in visual acuity were better than previously reported. As fragility of Bruch's membrane represents the basis of onset, recurrence and relapse are likely in patients exhibiting MNV, highlighting the need for regular follow-up.

Deep Anterior Lamellar Keratoplasty and Peripheral Lamellar Keratoplasty for a Case of Severe Peripheral Ulcerative Keratitis.

We experienced a rare case of severe peripheral ulcerative keratitis in a patient undergoing surgery combined with deep anterior lamellar keratoplasty (DALK) and peripheral lamellar keratoplasty (LK). A 63-year-old Japanese woman was referred to our hospital for the treatment of visual disturbance caused by peripheral ulcerative keratitis in the left eye. Although the inflammation subsided with topical and oral administration of steroids, peripheral ulcerative keratitis worsened 4 weeks after the medical treatment. Surgery combining DALK and peripheral LK, including the corneal limbus, was performed as treatment. Two weeks after the surgery, a double anterior chamber appeared, but it disappeared spontaneously. There was no postoperative rejection or intraocular pressure elevation. One year and 6 months after the surgery, the inflammation did not recur, the cornea remained transparent, and the thickness of the cornea was maintained. In conclusion, combined DALK and peripheral LK may be a surgical option for treating severe peripheral ulcerative keratitis.

Severe foveal hypoplasia and macular degeneration in Stickler syndrome caused by missense mutation in COL2A1 gene.

BACKGROUND: The aim is to determine the retinal changes in patients with Stickler syndrome caused by a p.R565C missense mutation of the COL2A1 gene. METHODS: We reviewed the clinical records of 10 eyes of six patients from two families with the Stickler syndrome. The members of both families were heterozygous for the p.R565C mutation. The clinical features including the visual acuity, fundus appearances, fundus autofluorescence (FAF), optical coherence tomographic (OCT) images, and electroretinograms were examined. RESULTS: Myopia of -12 diopters (D) to -24 D with an average of -16.8 D was observed in 9 eyes of the 5 patients. The FAF images showed different degrees of hyper and hypoautofluorescent patterns in the macula in all but the two youngest patients (7 of 9 eyes, 78%). The OCT images showed the absence of a foveal pit and destruction of the outer retinal layers in the macular area in all patients. The ellipsoid zone (EZ) in the macular region was disrupted in eight eyes (80%) of which seven were fovea sparing. CONCLUSION: Two families with Stickler syndrome with the p.R565C mutation showed more severe foveal hypoplasia, macular degeneration, and extensive retinal degeneration. A correlation of the OCT and FAF images with the genotype is helpful in determining the prognosis of Stickler syndrome.

Branch Retinal Artery Occlusions, Paracentral Acute Middle Maculopathy and Acute Macular Neuroretinopathy After COVID-19 Vaccinations.

Purpose: Potential retinal adverse events after COVID-19 vaccinations reported previously include paracentral acute middle maculopathy (PAMM), acute macular neuroretinopathy (AMN), and central serous chorioretinopathy. We report four cases of branch retinal artery occlusion (BRAO), one case of PAMM, and one case of AMN that occurred after administration of the Pfizer-BioNTech COVID-19 vaccine. Patients and Methods: We retrospectively reviewed the medical records of six patients who presented to Yame General Hospital or Oita University Hospital from July through October 2021. Results: Four patients (2 males) presented with visual field defects associated with BRAO, one male patient with PAMM, and one female patient with AMN after receiving the Pfizer-BioNTech COVID-19 vaccine. The mean age was 59.3 years; the mean best-corrected visual acuity was 20/21. The mean time from the last vaccination to the onset of visual field defect was 22.8 days. Five patients had received two doses of the vaccine and one patient one dose. Patients' medical history included diabetes mellitus in case 2, hypertension in cases 2, 3 and 6, and Alport syndrome and end-stage renal disease in case 6 for which the patient was undergoing regular hemodialysis. Conclusion: Although rare, retinal adverse events may occur after COVID-19 vaccinations. Further studies with a larger sample size should determine whether these retinal abnormalities are causally associated with COVID-19 vaccinations or just coincidental. Potential risks of BRAO/PAMM/AMN after COVID-19 vaccinations must be carefully weighed against the substantial benefit of COVID-19 vaccinations.

Optical coherence tomographic assessment of dynamic macular changes in patients with Vogt-Koyanagi-Harada disease.

To determine the relationship between visual acuity and three-dimensional optical coherence tomographic (3D-OCT) findings of the macula in eyes with Vogt-Koyanagi-Harada (VKH) disease. Twelve eyes of six patients (three men and three woman, average age 53.2 years) in the acute phase of VKH disease were examined with a 3D-OCT instrument. All of the eyes had a serous macular detachment. The height of the sensory retinal detachment (SRD) and the sensory retinal thickness (SRT) were measured by OCT before treatment (acute stage) and at the convalescent stage. The correlation between the retinal morphology and visual acuity was evaluated. The height of the SRD and the SRT were 612.5 ± 371.2 and 136. 7 ± 22.0 µm, respectively. The initial visual acuity was significantly worse in eyes with a higher SRD (P = 0.014, r = 0.68) but the correlation between initial visual acuity and SRT was not significant. The recovery of visual acuity was attained in 50.7 ± 44.1 days and the complete resolution of the SRD was attained in 30.5 ± 23.2 days. The final visual acuity was attained several days after the complete resolution of the SRD in all four eyes of patients over 60 years of age, but the recovery of visual acuity often preceded the complete resolution of the SRD. The OCT images provided a noninvasive indicator of the severity of the disease and dynamic changes in the macular morphology, reflecting the effect of treatment in association with the improvement in visual acuity. Monitoring the SRD by 3D-OCT may guide the tapering of systemic corticosteroid treatment.

Contribution of the clock gene DEC2 to VEGF mRNA upregulation by modulation of HIF1α protein levels in hypoxic MIO-M1 cells, a human cell line of retinal glial (Müller) cells.

PURPOSE: Clock genes are components of the molecular clock. Their malfunction is thought to increase the risk of numerous diseases, including cancer. Vascular endothelial growth factor (VEGF) has a pivotal role in angiogenesis, and its expression levels are controlled by clock genes in tumor cells. Ophthalmic diseases such as age-related macular degeneration, proliferative diabetic retinopathy, and neovascular glaucoma are also associated with abnormal angiogenesis followed by upregulation of VEGF in the eye. In the present study, we aimed to uncover the relationship between clock genes and VEGF in the eye. STUDY DESIGN: Laboratory investigation METHODS: Oxygen-induced retinopathy (OIR) mice were prepared to mimic hypoxic conditions in the eye. Deferoxamine (DFO) was used to mimic hypoxic conditions in human Müller cell line MIO-M1 cells. Expression levels of mRNA and protein were quantified by quantitative reverse transcription polymerase chain reaction and Western blot analysis, respectively. RESULTS: In the retinas of OIR mice, the expression levels of Vegf and the clock gene Dec2 increased transiently, and their temporal profiles were correlated. Knockdown of DEC2 resulted in a significant (26.7%) reduction of VEGF expression in MIO-M1 cells under hypoxia-mimicking conditions induced by DFO (P < .05). Levels of HIF1α protein were also reduced significantly, by 60.2%, in MIO-M1 cells treated with siRNA against the DEC2 gene (P < .05). Moreover, HIF1α levels showed a significant (2.5-fold) increase in MIO-M1 cells overexpressing DEC2 (P < .05). CONCLUSION: DEC2 could upregulate retinal VEGF gene expression through modulation of HIF1α levels under hypoxic conditions.

A Japanese Family With Autosomal Dominant Oculocutaneous Albinism Type 4.

Purpose: We report the clinical characteristics of a Japanese family with autosomal dominant oculocutaneous albinism and a SLC45A2 gene mutation. Methods: A total of 16 members of a Japanese family with general hypopigmentation and foveal hypoplasia underwent detailed clinical examinations. We evaluated the severity of foveal hypoplasia using spectral-domain optical coherence tomography (SD-OCT) and graded it according to the criteria of Thomas et al. DNA was extracted from 17 family members and used for genome-wide single nucleotide polymorphism genotyping and linkage analysis. Mutational search was performed for the SLC45A2 gene responsible for oculocutaneous albinism type 4 (OCA4). Results: All 16 patients exhibited hypopigmentation of their hair and/or iris. They showed foveal hypoplasia, including 3 patients with grade 1 foveal hypoplasia, 7 with grade 2, and 6 with grade 3. No patient had grade 4 foveal hypoplasia. Optical coherence tomography showed macular ganglion cell complex thinning in the temporal area, and a slight reduction of visual field sensitivity in the centrotemporal area. A maximum multipoint parametric logarithm of the odds (LOD) score of approximately 2.00 to 3.56 was obtained on chromosome 5, spanning approximately 7.2 Mb between rs13187570 and rs395967 that included the SLC45A2 gene. All affected members showed a novel heterozygous variant, c.208T>C (p.Y70H), in the SLC45A2 gene, which supported a diagnosis of OCA4. Conclusions: The present study reports a very rare family with autosomal dominant OCA4 whose diagnosis was confirmed by a mutational analysis. Most family members exhibited mild general hypopigmentation and low-grade foveal hypoplasia.

Three cases of pigmented cosmetic dermatitis-like eruptions associated with primary Sjögren's syndrome or anti-SSA antibody.

Pigmented cosmetic dermatitis-like (Riehl's melanosis-like) pigmentation was reported in three of 27 patients with primary Sjögren's syndrome. But case reports of such eruptions are rare. We describe three cases of such eruptions associated with primary Sjögren's syndrome or anti-SSA antibody and possible associations with specific types of human leukocyte antigen (HLA) and infiltrating lymphocytes. These middle-aged Japanese women had reticular facial pigmentation and histopathological examination revealed interface dermatitis, melanophages, and dense lymphocytic infiltration around hair follicles and sweat ducts. HLA typing revealed common antigenic equivalents or genetic typing of HLA-A2, DR52, DPA1(02:02) and DPB1(05:01). Immunohistochemical staining revealed major subsets of T cells to be CD8 and CD45RO. Some Foxp3- and few IL17-positive cells were found in strong contrast to the major CD4 subset of infiltrated T cells in annular erythema associated with Sjögren's syndrome. Apparently, our patients' pigmentation represented a specific etiology associated with primary Sjögren's syndrome or anti-SSA antibody.

p38 MAP kinase inhibitor suppresses transforming growth factor-ß2-induced type 1 collagen production in trabecular meshwork cells.

Glaucoma is an age-related neurodegenerative disease of retinal ganglion cells, and appropriate turnover of the extracellular matrix in the trabecular meshwork is important in its pathology. Here, we report the effects of Rho-associated kinase (ROCK) and p38 MAP kinase on transforming growth factor (TGF)-ß2-induced type I collagen production in human trabecular meshwork cells. TGF-ß2 increased RhoA activity, actin polymerization, and myosin light chain 2 phosphorylation. These effects were significantly inhibited by Y-27632, but not SB203580. TGF-ß2 also increased promoter activity, mRNA synthesis, and protein expression of COL1A2. These effects were significantly inhibited by SB203580, but not Y-27632. Additionally, Y-27632 did not significantly inhibit TGF-ß2-induced promoter activation, or phosphorylation or nuclear translocation of Smad2/3, whereas SB203580 partially suppressed these processes. Collectively, TGF-ß2-induced production of type 1 collagen is suppressed by p38 inhibition and accompanied by partial inactivation of Smad2/3, in human trabecular meshwork cells.

p38 MAPK mediates the expression of type I collagen induced by TGF-beta 2 in human retinal pigment epithelial cells ARPE-19.

PURPOSE: Transforming growth factor (TGF)-beta has been implicated as the key mediator of proliferative vitreoretinopathy, but the cellular mechanisms by which TGF-beta induces extracellular matrix protein (ECM) synthesis are not fully understood. The current study was conducted to examine whether the mitogen-activated protein kinase (MAPK) pathway is involved in TGF-beta 2-induced collagen expression in retinal pigment epithelial cells. METHODS: Human retinal pigment epithelial cells ARPE-19 were cultured and stimulated with various concentrations of TGF-beta 2. The type I collagen gene (COL1A1, COL1A2) expression induced by TGF-beta 2 was evaluated by real-time RT-PCR. Synthesis of type I collagen was evaluated by the concentration of the C-terminal propeptide of type I (PICP) in the medium. The activation of MAPK pathways by TGF-beta 2 was assessed by immunoblot with anti-phospho-p38 and anti-phospho-extracellular signal-regulated kinase (ERK)1/2 antibodies. The role of MAPK was assessed using biochemical inhibitors. To examine the transcriptional activities of COL1A1 and COL1A2, luciferase reporter assays were also performed. RESULTS: mRNA expression of COL1A1 and COL1A2 and type I collagen synthesis were activated by TGF-beta 2. Both ERK and p38 MAPK pathways were also activated by TGF-beta 2. The biochemical blockade of p38 MAPK activation, but not ERK activation, inhibited TGF-beta 2-induced type I collagen mRNA expression and type I collagen synthesis. Moreover, blockade of the p38 MAPK pathway inhibited the increase in both COL1A1 and COL1A2 promoter activities when induced by TGF-beta 2. CONCLUSIONS: TGF-beta 2 activates p38 MAPK and p38 MAPK plays a role in relaying the TGF-beta 2 signal to type I collagen production in the retinal pigment epithelium.