Progression of Polypoidal Lesions Associated with Exudative Recurrence in Polypoidal Choroidal Vasculopathy.

PURPOSE: To investigate the characteristics of the branching vascular network (BVN) and polypoidal lesions in polypoidal choroidal vasculopathy (PCV) to determine near-term indicators that may predict exudative recurrence. DESIGN: Retrospective cohort study. PARTICIPANTS: Patients with PCV receiving anti-vascular endothelial growth factor (VEGF) monotherapy or anti-VEGF plus photodynamic therapy were followed for at least 1 year using swept-source OCT angiography (SS-OCTA) imaging. METHODS: Patients were divided into 2 groups based on whether exudative recurrence occurred during follow-up. Multiple parameters were collected and compared between the 2 groups, such as age, gender, visual acuity, number of polypoidal lesions, lesion area at the first SS-OCTA visit, and total lesion area change from the first SS-OCTA visit to the last SS-OCTA visit. To evaluate the association between SS-OCTA imaging-based risk factors and the exudative recurrences, imaging features associated with PCV such as BVN growth and polypoidal lesion progression (enlargement, new appearance, and reappearance) at each follow-up visit were analyzed. The time intervals from the nonexudative visit with lesion progression to the corresponding exudative recurrence visit were documented to explore their association with exudative recurrences. Cox regression and logistic regression analyses were used. MAIN OUTCOME MEASURES: Association between BVN growth and polypoidal lesion progression with exudative recurrence. RESULTS: Thirty-one eyes of 31 patients (61% men) were included. Sixteen eyes had no recurrence of exudation, and 15 eyes had recurrence during follow-up. The average follow-up duration was 20.55 ± 6.86 months (range, 12-36 months). Overall, the recurrence group had worse best-corrected visual acuity (P = 0.019) and a greater increase in lesion area (P = 0.010). Logistical regression analysis showed that polypoidal lesion progression, including new appearance, enlargement, and reappearance of polypoidal lesions, was associated with exudative recurrences within 3 months (odds ratio, 26.67, 95% confidence interval, 3.77-188.54, P = 0.001). CONCLUSIONS: Growth of nonexudative BVN and progression of polypoidal lesions were found to be lesion characteristics associated with exudative recurrences, and progression of polypoidal lesions might serve as a stand-alone indicator for the near-term onset of exudation. In PCV, more frequent follow-up visits are recommended when polypoidal lesions show progression.

Fat mass and obesity-associated protein alleviates Aß1-40 induced retinal pigment epithelial cells degeneration via PKA/CREB signaling pathway.

Amyloid-ß (Aß) is thought to be a critical pathologic factor of retinal pigment epithelium (RPE) degeneration in age-related macular degeneration (AMD). Aß induces inflammatory responses in RPE cells and recent studies demonstrate the N6-methyladenosine (m6A) regulatory role in RPE cell inflammation. m6A is a reversible epigenetic posttranslational modification, but its relationship with Aß-induced RPE degeneration is yet to be thoroughly investigated. The present study explored the role and mechanism of m6A in Aß-induced RPE degeneration model. This model was induced via intravitreally injecting oligomeric Aß and the morphology of its retina was analyzed. One of m6A demethylases, the fat mass and obesity-associated (FTO) gene expression, was assessed. An m6A-messenger RNA (mRNA) epitranscriptomic microarray was employed for further bioinformatic analyses. It was confirmed that Aß induced FTO upregulation within the RPE. Hypopigmentation alterations and structural disorganization were observed in Aß-treated eyes, and inhibition of FTO exacerbated retinal degeneration and RPE impairment. Moreover, the m6A-mRNA epitranscriptomic microarray suggested that protein kinase A (PKA) was a target of FTO, and the PKA/cyclic AMP-responsive element binding (CREB) signaling pathway was involved in Aß-induced RPE degeneration. m6A-RNA binding protein immunoprecipitation confirmed that FTO demethylated PKA within the RPE cells of Aß-treated eyes. Altered expression of PKA and its downstream targets (CREB and brain-derived neurotrophic factor) was confirmed by quantitative reverse-transcription polymerase chain reaction and Western blot analyses. Hence, this study's findings shed light on FTO-mediated m6A modification in Aß-induced RPE degeneration and indicate potential therapeutic targets for AMD.

COMPARISON OF THREE INTERNAL LIMITING MEMBRANE PEELING TECHNIQUES FOR MYOPIC TRACTION MACULOPATHY WITH HIGH RISK OF POSTOPERATIVE MACULAR HOLE DEVELOPMENT.

PURPOSE: To compare three different internal limiting membrane (ILM) peeling techniques, including standard ILM peeling, fovea-sparing ILM peeling, and inverted ILM flap (ILMF), in the treatment of myopic traction maculopathy with high risk of postoperative macular hole development. METHOD: This retrospective cohort study enrolled 101 eyes suffering from lamellar macular hole combined with myopic traction maculopathy in 98 consecutive patients who underwent vitrectomy with either standard ILM peeling, fovea-sparing ILM peeling, or ILMF from July 2017 to August 2020. All patients were followed up for at least 12 months after surgery. Best-corrected visual acuity, macular anatomical outcomes, and postoperative full-thickness macular hole (FTMH) formation were evaluated. RESULTS: No significant differences were found among the three surgical groups in baseline characteristics. 12 months after surgery, the mean best-corrected visual acuity was significantly improved ( P < 0.001) and showed no significant differences among groups ( P = 0.452). None of the eyes in the ILMF group, five eyes (15.6%) in the standard ILM peeling group, and six eyes (17.1%) in the fovea-sparing ILM peeling group developed a postoperative FTMH ( P = 0.026). Logistic regression showed that the ILM peeling technique was an independent influencing factor for FTMH formation (OR = 0.209, P = 0.014). CONCLUSION: Compared with the standard ILM peeling or fovea-sparing ILM peeling technique, the ILMF technique resulted in similar visual outcomes but a relatively low incidence of postoperative FTMH in the treatment of lamellar macular hole combined with myopic traction maculopathy. Inverted ILM flap is an effective technique for treating myopic traction maculopathy with high risk of postoperative FTMH development.

Long-term surgical outcomes and prognostic factors of foveal detachment in pathologic myopia: based on the ATN classification.

BACKGROUND: To investigate the long-term surgical outcomes and prognostic factors of foveal detachment (FD) in pathological myopia. METHODS: This retrospective observational study included 59 patients with FD (61 eyes) who underwent pars plana vitrectomy at Shanghai General Hospital between June 2017 and July 2018 with follow-up for at least 24 months. Comprehensive ophthalmic examinations, including best-corrected visual acuity (BCVA) and swept-source optical coherence tomography, were assessed. Preoperative myopic maculopathy was evaluated according to the ATN classification. RESULTS: FD completely resolved in 59 of 61 eyes (96.7%). Mean duration of retinal reattachment was 12.10 ± 8.10 months. Mean logMAR BCVA improved from 1.34 ± 0.52 to 0.83 ± 0.43 at 24 months postoperatively (P < 0.001). Secondary macular hole occurred in 8 eyes (13.1%) with a mean period of 3.4 ± 4.1 weeks after primary surgery. In regression analyses, baseline myopic atrophy maculopathy (MAM) (B = 0.213, P = 0.005) and vitreomacular traction (VMT) (B = 0.292, P = 0.007) were adverse prognostic factors for postoperative BCVA. A more severe MAM revealed a delay in retinal reattachment (B = 5.670, P = 0.002). FD eyes with VMT (OR = 1.309, P = 0.003) or outer lamellar macular hole (O-LMH) (OR = 1.369, P < 0.001) were risk factors for postoperative secondary macular hole. CONCLUSIONS: Vitrectomy was effective in the long-term for treating FD. Careful consideration is needed for those with VMT or O-LMH due to the high risk of secondary macular hole after vitrectomy. FD eyes with more severe MAM tended to have poorer postoperative BCVA and extended periods of retinal reattachment.

TRIM31 inhibits NLRP3 inflammasome and pyroptosis of retinal pigment epithelial cells through ubiquitination of NLRP3.

NOD-like receptor protein 3 (NLRP3) is associated with age-related macular degeneration (AMD). Retinal pigment epithelial (RPE) cells serve as the immune defense of macula, and their dysfunction causes clinically relevant changes in AMD. In the present study, oxidized low-density lipoprotein (ox-LDL) activated the NLRP3 inflammasome in human RPE cell line ARPE-19. Our data showed that the expression of NLRP3, interleukin-1ß (IL-1ß), and caspase-1 and the release of IL-1ß in ARPE-19 cells were substantially increased by ox-LDL, whereas the addition of NLRP3 inhibitor INF39 dose-dependently reversed the effect of ox-LDL. Overexpression of tripartite motif-containing protein 31 (TRIM31) also suppressed the effect of ox-LDL in ARPE-19 cells. TRIM31 knockdown had similar effects with ox-LDL but INF39 could block the effect of TRIM31 knockdown. Moreover, TRIM31 could interact with NLRP3 in ARPE-19 cells. Overexpression of TRIM31 increased NLRP3 ubiquitination. In conclusion, the results propose that TRIM31 could enhance NLRP3 ubiquitination, therefore inhibiting NLRP3 inflammasome and pyroptosis in human RPE cells.

Functional evaluation with microperimetry in large idiopathic macular holes treated by a free internal limiting membrane flap tamponade technique.

BACKGROUND: Free internal limiting membrane (ILM) flap tamponade technique is an alternative choice for treating large idiopathic macular holes (IMHs). However, the functional recovery related to this surgical approach is not well-characterized. This study aimed to evaluate morphological and microperimetric outcomes 6 months after free ILM flap tamponade technique for large IMHs. METHODS: Twenty-two patients (22 eyes) with large IMHs (minimal diameter > 400 µm) were retrospectively enrolled in this study. All patients underwent 23-gauge pars plana vitrectomy with ILM peeling and free ILM flap tamponade procedures. Snellen best-corrected visual acuity (BCVA), optical coherence tomography (OCT), and MP-1 microperimetry were measured at baseline and 6 months after surgery. Associations of postoperative BCVA with retinal sensitivity were detected. RESULTS: Macular hole closure was achieved in 21 eyes (95.5%). Dislodgement of free ILM flap was found in non-closed eye. Mean logMAR BCVA improved from 1.10 ± 0.33 at baseline to 0.67 ± 0.32 at 6 months postoperatively (P < 0.001). The mean overall macular sensitivity and foveal fixation stability increased respectively from 8.58 ± 3.05 dB and 65.64 ± 17.28% before surgery to 11.55 ± 2.72 dB and 78.59 ± 13.00% at 6 months after surgery (P < 0.001). The mean change in foveal sensitivity (within 2°) was significantly greater than the change achieved for peri-foveal sensitivity (2° to 10°) by 1.50 ± 2.62 dB (P = 0.014). Linear regression analysis showed that postoperative logMAR BCVA was significantly associated with duration of symptom (B = 0.063, P = 0.001), preoperative logMAR BCVA (B = 0.770, P = 0.000), preoperative peri-foveal (B = - 0.065, P = 0.000) and foveal sensitivity (B = - 0.129, P = 0.000). Moreover, multiple regression model revealed that preoperative foveal sensitivity was independently associated with postoperative logMAR BCVA (B = - 0.430, P = 0.040). CONCLUSIONS: Vitrectomy combined with ILM peeling and free ILM flap tamponade technique results in effective morphological and functional recovery for large IMHs. Preoperative foveal sensitivity might be a prognostic indicator for postoperative BCVA.

Autophagy activated via GRP78 to alleviate endoplasmic reticulum stress for cell survival in blue light-mediated damage of A2E-laden RPEs.

BACKGROUND: Retinal pigment epithelium cells (RPEs) are critical for maintaining retinal homeostasis. Accumulation of age-related lipofuscin, N-retinylidene-N-retinylethanolamine (A2E), makes RPEs vulnerable to blue light-mediated damage, which represents an initial cause of some retinal degenerative diseases. This study investigated the activation of autophagy and the signaling pathway involved in glucose-related protein 78 (GRP78) induced autophagy in blue light-mediated damage of A2E-laden RPEs. In addition, we explored whether autophagy could play a protective role by alleviating endoplasmic reticulum (ER) stress to promote RPEs survival. METHODS: RPEs were incubated with 25 µM A2E for 2 h and exposed to blue light for 20 min. The expression of ER stress-related apoptotic proteins, CHOP and caspase-12, as well as autophagy marker LC3 were measured by western blot analysis. Autophagosomes were observed by both transmission electron microscopy and immunofluorescence assays. GRP78 interference performed by short hairpin RNA (shRNA) was used to identify the signaling pathway involved in GRP78 induced autophagy. Cell death was assessed using TUNEL analysis. RESULTS: Treatment with A2E and blue light markedly increased the expression of ER stress-related apoptotic molecules CHOP and caspase-12. The activation of autophagy was recognized by observing autophagosomes at ultrastructural level. Additionally, punctate distributions of LC3 immunofluorescence and enhanced conversions of LC3-I to LC3-II were found in A2E and blue light-treated RPEs. Moreover, GRP78 interference reduced AMPK phosphorylation and promoted mTOR activity, thereby downregulating autophagy. In addition, the inhibition of autophagy made RPEs vulnerable to A2E and blue light damage. In contrast, the autophagy inducer rapamycin alleviated ER stress to promote RPEs survival. CONCLUSIONS: GRP78 activates autophagy via AMPK/mTOR in blue light-mediated damage of A2E-laden RPEs in vitro. Autophagy may be a vital endogenous cytoprotective process to alleviate stress for RPEs survival in retinal degenerative diseases.

Involvement of XBP1s in Blue Light-Induced A2E-Containing Retinal Pigment Epithelium Cell Death.

PURPOSE: Retinal pigment epithelium (RPE) cell dysfunction is essential to the development of retinal degenerative disease. This study was designed to investigate how spliced X-box-binding protein 1 (XBP1s) regulates different modes of RPE cell death in vitro. METHODS: Human ARPE19 cells were incubated with 25 µM N-retinylidene-N-retinylethanolamine (A2E) and irradiated with blue light. Expressions of glucose-regulated protein 78 (GRP78) and XBP1s were detected by real-time quantitative PCR and Western blot. STF-083010 was used to suppress XBP1s expression. ARPE19 cell apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling and flow cytometry. Receptor-interacting protein kinase-3 (RIP3) was detected by Western blot. Changes in the morphology of ARPE19 cells were identified by transmission electron microscopy. RESULTS: Blue light-induced A2E-containing ARPE19 cell damage caused a transient elevation of GRP78 and XBP1s, while RIP3 rose in the late stage. STF-083010 effectively inhibited XBP1s expression and brought about the aggravation of apoptosis together with an alleviation of RIP3 expression. Most of the dying cells exhibited apoptotic morphology. CONCLUSION: A2E, along with blue light, brought about apoptosis and necroptosis of ARPE19 cells, and XBP1s was transiently elevated. The suppression of XBP1s induced ARPE19 cell death by promoting apoptosis rather than necroptosis. XBP1s might play a role in the pathogenesis of retinal degenerative diseases.

Expression of endoplasmic reticulum stress markers GRP78 and CHOP induced by oxidative stress in blue light-mediated damage of A2E-containing retinal pigment epithelium cells.

AIMS: Age-related lipofuscin N-retinylidene-N-retinylethanolamine (A2E) accumulated in human retinal pigment epithelium (RPE) cells confers susceptibility to blue light-mediated damage, which represents one pathogenesis of age-related macular degeneration. This study investigated the expression of 2 best-characterized endoplasmic reticulum (ER) stress markers, glucose-related protein 78 (GRP78) and C/EBP homologous protein (CHOP), as well as their regulation by oxidative stress after blue light-mediated damage of A2E-containing RPE cells. METHODS: ARPE-19 cells were incubated with A2E (10, 25, 50 µM) for 2 h and exposed to blue light for 20 min. A2E distributions in RPE cells were assessed via laser scanning confocal microscope and liquid chromatography-mass spectrometry. Cell viability was measured by a Cell Titer 96 Aqueous One Solution cell proliferation assay. The quantity of intracellular reactive oxygen species (ROS) was detected by dihydroethidium fluorescence using flow cytometry. Expressions of GRP78 and CHOP were measured at both mRNA and protein levels. To examine the role of oxidative stress in regulating GRP78 and CHOP expression, RPE cells were pretreated with the antioxidant N-acetylcysteine (NAC) for 2 h. RNA interference of GRP78 performed by short hairpin RNA was used to evaluate the effect of GRP78 in blue light-mediated damage of RPE cells. RESULTS: After blue light exposure, A2E-treated RPE cells showed a gradual decrease in cell viability and a particular increase in ROS levels. Meanwhile, the expressions of GRP78 and CHOP in A2E-treated RPE cells were significantly increased at different time points after illumination. Pretreatment with NAC attenuated the expression of 2 ER stress markers, especially CHOP in A2E and blue light-treated RPE cells. Silencing of GRP78 by RNA interference upregulated CHOP and caspase-12 expression as well as aggravated the blue light-mediated damage of A2E-laden RPE cells. CONCLUSION: RPE cells exhibited ROS accumulation and subsequent elevation of GRP78 and CHOP expression after A2E and blue light-induced damage. The ROS scavenger NAC diminished ER stress protein expression, suggesting a connection between ER and oxidative stress in blue light-mediated damage of A2E-containing RPE cells. Besides, GRP78 may play a protective role in it.

Growth of nonexudative macular neovascularization in age-related macular degeneration: an indicator of biological lesion activity.

PURPOSE: To investigate the growth of nonexudative macular neovascularization (MNV) in age-related macular degeneration (AMD) using swept-source optical coherence tomography angiography (SS-OCTA). METHODS: Patients with treatment-naïve nonexudative AMD in one eye and exudative AMD in the fellow eye who underwent SS-OCTA imaging for at least 12 months were retrospectively reviewed. The MNV area measurement was quantified in eyes with treatment-naïve nonexudative MNV using ImageJ for analysing the correlation between MNV growth and the onset of exudation, as well as evaluating the consistency of the MNV growth rate during the subclinical and exudative stages. Kaplan-Meier survival analysis and logistic regression analyses were used. RESULTS: In total, 45 eyes with treatment-naïve nonexudative AMD from 45 patients were enrolled. Treatment-naïve nonexudative MNV was identified in 21 eyes (46.67%) at baseline. The development of exudative findings was noted in eight eyes (17.78%), including six eyes with previously noted nonexudative MNV. Eyes with growing MNV (increase in area ≥50% within 12 months) had an increased risk of exudation and developed exudation earlier than eyes with stable MNV (13.60 [6.43-20.77] months versus 31.11 [26.61-35.62] months, P < 0.0001, Log-rank test). Consistent growth pattern of MNV lesions was further identified in eyes with growing MNV during anti-VEGF treatment. CONCLUSION: SS-OCTA allows to qualitatively and quantitatively evaluate nonexudative MNV in AMD patients. Growing MNV involved higher probabilities and a faster onset of exudation compared to stable MNV. Identifying the growth of MNV on OCTA might be helpful for establishing treatment strategies and follow-up planning.

METTL3-mediated m6A modification of HMGA2 mRNA promotes subretinal fibrosis and epithelial-mesenchymal transition.

Subretinal fibrosis is a major cause of the poor visual prognosis for patients with neovascular age-related macular degeneration (nAMD). Myofibroblasts originated from retinal pigment epithelial (RPE) cells through epithelial-mesenchymal transition (EMT) contribute to the fibrosis formation. N6-Methyladenosine (m6A) modification has been implicated in the EMT process and multiple fibrotic diseases. The role of m6A modification in EMT-related subretinal fibrosis has not yet been elucidated. In this study, we found that during subretinal fibrosis in the mouse model of laser-induced choroidal neovascularization, METTL3 was upregulated in RPE cells. Through m6A epitranscriptomic microarray and further verification, high-mobility group AT-hook 2 (HMGA2) was identified as the key downstream target of METTL3, subsequently activating potent EMT-inducing transcription factor SNAIL. Finally, by subretinal injections of adeno-associated virus vectors, we confirmed that METTL3 deficiency in RPE cells could efficiently attenuate subretinal fibrosis in vivo. In conclusion, our present research identified an epigenetic mechanism of METTL3-m6A-HMGA2 in subretinal fibrosis and EMT of RPE cells, providing a novel therapeutic target for subretinal fibrosis secondary to nAMD.

Association between Different Grades of Myopic Tractional Maculopathy and OCT-Based Macular Scleral Deformation.

Purpose: To investigate the characteristics of macular outward scleral height (MOSH) in different grades of myopic tractional maculopathy (MTM) and explore the risk factors for MTM. Methods: A total of 188 eyes (188 participants) with high myopia were divided into the no MTM (nMTM) group and the MTM group, which was further graded into foveoschisis, foveal detachment, full-thickness macular hole, and macular hole with retinal detachment. Swept-source optical coherence tomography was used to measure the MOSH. Results: No significant differences were found in axial length between the nMTM and MTM groups (p = 0.295). The MOSH was significantly higher in the MTM group (p < 0.001), which was identified as a risk factor for MTM (OR = 1.108, p < 0.001). The proportion of eyes with severe atrophic myopic maculopathy (AMM) was higher in the MTM group (28.48%) (p = 0.003). The macular hole with foveoschisis (MH/FS+) subgroup presented a higher average MOSH (p = 0.012) and more severe AMM (p = 0.009) than the macular hole without foveoschisis (MH/FS−) subgroup. Conclusion: MOSH would be more suitable for estimating MTM occurrence than axial length. The grading of AMM helps to evaluate the severity of MTM. The categorization of MH/FS− as a distinct grade from MH/FS+ might be preferable.

Association of Microvasculature and Macular Sensitivity in Idiopathic Macular Epiretinal Membrane: Using OCT Angiography and Microperimetry.

Purpose: To investigate the correlation between retinal capillary structure and macular function in patients with idiopathic epiretinal membrane (iERM) by using optical coherence tomography angiography (OCTA) and microperimetry. Methods: This retrospective and observational study included 30 idiopathic ERM eyes of 30 consecutive patients. OCTA was performed to evaluate macular microvasculature including the superficial capillary plexus, deep capillary plexus, and foveal avascular zone. Best corrected visual acuity (BCVA) and microperimetry were measured at baseline and 3 months after surgery. Associations between macular microvasculature and visual function were assessed. Results: Visual function including BCVA and macular sensitivity improved significantly at 3 months post-operatively (p < 0.001). At baseline, BCVA was positively correlated with foveal or parafoveal sensitivities and negatively correlated with central foveal thickness (p < 0.05). Pre-operative foveal sensitivity was significantly correlated with the vessel density of foveal or parafoveal superficial capillary plexus (p < 0.05). A multiple regression model revealed that pre-operative vessel density of foveal deep capillary plexus was an independent positive prognostic factor for post-operative BCVA (B = -0.020 ± 0.006, p = 0.006) and macular sensitivity (B = 0.200 ± 0.081, p = 0.027). Conclusion: Integrated evaluation of iERM by using OCTA and microperimetry shows an association between microvasculature and macular sensitivity. Pre-operative vessel density of foveal deep capillary plexus assessed by OCTA may be a potentially valuable prognostic factor for iERM surgery.

Human retinal pigment epithelial cells are protected against hypoxia by BNIP3.

BACKGROUND: Hypoxia has been implicated in the process of retinal pigment epithelium (RPE) dysfunction. However, recent studies suggest that hypoxia contributes to survival rather than cell death through induction of Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNIP3)-dependent autophagy. In contrast, persistent oxidative stress was found to result in autophagy dysregulation in RPE cells. These seemingly contradictory findings led us to investigate the potential role of BNIP3, a crucial mediator of hypoxia-induced autophagy, in the context of hypoxic RPE cells. METHODS: Human RPE D407 cells were treated with low-oxygen conditions, and cell growth, apoptosis, and autophagy was assessed by Cell Counting Kit-8 assay, flow cytometry analysis and immunofluorescence staining, respectively. RESULTS: Hypoxic conditions simultaneously triggered a large amount of apoptosis and inhibited autophagy. Moreover, hypoxia led to severe impairments, including the stimulation of reactive oxygen species, and reduction of mitochondrial membrane potential, and adenosine triphosphate production. The stimulation of autophagy by rapamycin inhibited hypoxia-induced severe impairments to a great extent. Interestingly, similar results were observed for BNIP3 overexpression, which can be largely blocked by 3-MA, a well-defined inhibitor of autophagy. Moreover, BNIP3 knockdown further aggravated hypoxia-induced impairments in D407 cells, which can be reversed by rapamycin. CONCLUSIONS: Collectively, these results indicated that BNIP3 can protect human retinal pigmented epithelial cells under hypoxic conditions by inducing autophagy.

ROS production and mitochondrial dysfunction driven by PU.1-regulated NOX4-p22phox activation in Aß-induced retinal pigment epithelial cell injury.

Rationale: Amyloid ß (Aß) deposition, an essential pathological process in age-related macular degeneration (AMD), causes retinal pigment epithelium (RPE) degeneration driven mostly by oxidative stress. However, despite intense investigations, the extent to which overoxidation contributes to Aß-mediated RPE damage and its potential mechanism has not been fully elucidated. Methods: We performed tandem mass-tagged (TMT) mass spectrometry (MS) and bioinformatic analysis of the RPE-choroid complex in an Aß1-40-induced mouse model of retinal degeneration to obtain a comprehensive proteomic profile. Key regulators in this model were confirmed by reactive oxygen species (ROS) detection, mitochondrial ROS assay, oxygen consumption rate (OCR) measurement, gene knockout experiment, chromatin immunoprecipitation (ChIP), and luciferase assay. Results: A total of 4243 proteins were identified, 1069 of which were significantly affected by Aß1-40 and found to be enriched in oxidation-related pathways by bioinformatic analysis. Moreover, NADPH oxidases were identified as hub proteins in Aß1-40-mediated oxidative stress, as evidenced by mitochondrial dysfunction and reactive oxygen species overproduction. By motif and binding site analyses, we found that the transcription factor PU.1/Spi1 acted as a master regulator of the activation of NADPH oxidases, especially the NOX4-p22phox complex. Also, PU.1 silencing impeded RPE oxidative stress and mitochondrial dysfunction and rescued the retinal structure and function. Conclusion: Our study suggests that PU.1 is a novel therapeutic target for AMD, and the regulation of PU.1 expression represents a potentially novel approach against excessive oxidative stress in Aß-driven RPE injury.

MicroRNA Expression Patterns Involved in Amyloid Beta-Induced Retinal Degeneration.

Purpose: Dry age-related macular degeneration (AMD) is characterized by the accumulation of drusen under Bruch's membrane, and amyloid beta (Aß) is speculated to be one of the key pathologic factors. While the detrimental effects of Aß on retinas have been widely explored, Aß-induced epigenetic regulatory changes have yet to be fully investigated. We therefore aimed to identify the microRNA (miRNA) expression profiles in an Aß-induced mouse model of retinal degeneration. Methods: C57BL/6 mice were intravitreally injected with Aß1-40 or PBS and the eye tissues were collected for hematoxylin and eosin (H&E) staining, apoptosis immunofluorescence staining, and miRNA profiling. After filtering, 10 miRNAs and their target genes were chosen for quantitative RT-PCR (qRT-PCR) confirmations. Pathway analyses were employed for further bioinformatic analyses. Results: Hematoxylin and eosin-stained sections of retinal pigment epithelium (RPE)/neural retina tissue demonstrated degenerative alterations, and immunofluorescence testing revealed apoptosis within the retina after Aß treatments. MicroRNA profiling revealed 61 miRNAs that were differentially expressed between the model and the control group. Among these, 38 miRNAs were upregulated (fold change > 1.5, P < 0.05) and 23 miRNAs were downregulated (fold change < 0.667, P < 0.05). Five of the 10 selected miRNAs (miR-142, miR-216, miR-155, miR-223, and miR-433) as well as several key target genes (CFH, IGF-1R, c-MET, and ABCA1) were confirmed by qRT-PCR analyses. Conclusions: Our study is the first to profile the miRNA expression patterns and suggests that Aß accumulation could lead to relevant biochemical alternations such as complement activation, barrier impairment, apoptosis, and positive feedback of Aß production.

Tumor enucleation specimens of small renal tumors more frequently have a positive surgical margin than partial nephrectomy specimens, but this is not associated with local tumor recurrence.

Approaches to nephron-sparing surgeries (NSS) of renal lesions include partial nephrectomy (PN) and tumor enucleation (TE). Our objective was to examine the pathology of the pseudocapsule and status of the surgical margin in small renal masses treated by NSS and to correlate these findings with the surgical and oncological outcomes. All consecutive renal TE and PN specimens obtained during the period between January 2012 and December 2014, of which clinical follow-up was available, were included in this study. Pathologic features and clinical data were reviewed and analyzed. A total of 117 NSS specimens (59 EN, 58 PN) were reviewed. Clear cell renal cell carcinomas and paraganglioma had the thickest pseudocapsules (0.36 mm), while angiomyolipomas did not form a well-defined pseudocapsule. Other tumors were intermediate in their characteristics. The positive margin rate for TE and PN was 17.2 and 0 %, respectively. Compared to PN, TE involved a significantly shorter procedure time, less blood loss, and fewer post-operative complications. None of the patients from either group was found to have a local recurrence after follow-up imaging. Although positive surgical margins were more frequently seen in TE specimens, local tumor recurrence was comparable to PN. Thus, TE is a reasonable choice for pT1 renal tumors, especially for those without a prominent infiltrative growth pattern.

Elevated p53 Activities Restrict Differentiation Potential of MicroRNA-Deficient Pluripotent Stem Cells.

Pluripotent stem cells (PSCs) deficient for microRNAs (miRNAs), such as Dgcr8-/- or Dicer-/- embryonic stem cells (ESCs), contain no mature miRNA and cannot differentiate into somatic cells. How miRNA deficiency causes differentiation defects remains poorly understood. Here, we report that miR-302 is sufficient to enable neural differentiation of differentiation-incompetent Dgcr8-/- ESCs. Our data showed that miR-302 directly suppresses the tumor suppressor p53, which is modestly upregulated in Dgcr8-/- ESCs and serves as a barrier restricting neural differentiation. We demonstrated that direct inactivation of p53 by SV40 large T antigen, a short hairpin RNA against Trp53, or genetic ablation of Trp53 in Dgcr8-/- PSCs enables neural differentiation, while activation of p53 by the MDM2 inhibitor nutlin-3a in wild-type ESCs inhibits neural differentiation. Together, we demonstrate that a major function of miRNAs in neural differentiation is suppression of p53 and that modest activation of p53 blocks neural differentiation of miRNA-deficient PSCs.

Phenylhexyl isothiocyanate inhibits histone deacetylases and remodels chromatins to induce growth arrest in human leukemia cells.

Natural isothiocyanates, present in cruciferous vegetables and synthetic phenylhexyl isothiocyanate (PHI) are chemopreventive agents which act by blocking the initiation of carcinogen-induced tumors in rodents. We have demonstrated that isothiocyanates are also growth regulators, inhibiting cell cycle cdk activity and up-regulating inhibitor p21WAF1 (p21) in cancer cells. The up-stream mechanism to modulate cell cycle progression remained to be elucidated. Here, we have demonstrated that exposure of HL-60 leukemia cells to PHI induced G1 arrest and apoptosis. The hypothesis that PHI inhibits cell growth via chromatin remodeling was investigated. PHI mediates the complex cross talk between chromatin and DNA, and it was demonstrated for the first time as an inhibitor of histone deacetylases (HDAC). Thus, the HDAC activity in PHI-exposed HL-60 cells was reduced. Additionally, PHI reduced the expression of HDAC and increased the level of acetyl transferase p300, in favor of accumulation of acetylated histones. Within hours, global acetylation of histones was enhanced. PHI further mediated selective alterations of histone methylation, with a pattern consistent to the marks of transcription competent chromatins. The relationship between acetylated histones and p21 was examined by chromatin immunoprecipitation (ChIP) assay. Chromatins from cells exposed to PHI contained more p21 DNA in the precipitates of hyperacetylated histones, indicating more accessibility of transcription machinery to the p21 promoter after chromatin unfolding. The cell cycle inhibitors were activated as a result. In contrast to the PHI-induced apoptosis in HL-60 cells, which was mediated by caspase-9 up-regulation and bcl-2 reduction, PHI did not induce significant apoptosis in the mononuclear cells from normal peripheral blood and bone marrow. The results revealed a potential selective effect of isothiocyanates to inhibit the growth of malignant cells.

Epigenetic mechanism of growth inhibition induced by phenylhexyl isothiocyanate in prostate cancer cells.

BACKGROUND: Isothiocyanates, the constituents of cruciferous vegetables, may be able to prevent prostate cancer. The hypothesis that they could remodel chromatins and activate cell cycle inhibitors, such as p21 for growth inhibition, was tested. MATERIALS AND METHODS: Prostate cancer LNCaP cells were exposed to phenylhexyl isothiocyanate (PHI). The status of histone acetylation and the activity of histone deacetylases (HDAC) were investigated. The association of p21 with hyperacetylated histones was examined by chromatin immunoprecipitation. RESULTS: The PHI-exposed LNCaP cells had diminished activity of HDAC 1 and 2. Global and selective histone acetylation was enhanced, consistent with the signs of chromatin unfolding. The hyperacetylated histones increased accessibility to the p21 promoter for transcription, leading to G1 arrest and apoptosis. CONCLUSION: PHI inhibited the activity of HDAC and remodeled chromatins to activate p21 for cell cycle arrest, underlying an epigenetic mechanism regulating the growth of prostate cancer cells.