A selective ER-phagy exerts neuroprotective effects via modulation of α-synuclein clearance in parkinsonian models.

The endoplasmic reticulum (ER) is selectively degraded by ER-phagy to maintain cell homeostasis. α-synuclein accumulates in the ER, causing ER stress that contributes to neurodegeneration in Parkinson's disease (PD), but the role of ER-phagy in α-synuclein modulation is largely unknown. Here, we investigated the mechanisms by which ER-phagy selectively recognizes α-synuclein for degradation in the ER. We found that ER-phagy played an important role in the degradation of α-synuclein and recovery of ER function through interaction with FAM134B, where calnexin is required for the selective FAM134B-mediated α-synuclein clearance via ER-phagy. Overexpression of α-synuclein in the ER of the substantia nigra (SN) resulted in marked loss of dopaminergic neurons and motor deficits, mimicking PD characteristics. However, enhancement of ER-phagy using FAM134B overexpression in the SN exerted neuroprotective effects on dopaminergic neurons and recovered motor performance. These data suggest that ER-phagy represents a specific ER clearance mechanism for the degradation of α-synuclein.

Immune activation during Pseudomonas infection causes local cell wall remodeling and alters AGP accumulation.

The plant cell boundary generally comprises constituents of the primary and secondary cell wall (CW) that are deposited sequentially during development. Although it is known that the CW acts as a barrier against phytopathogens and undergoes modifications to limit their invasion, the extent, sequence, and requirements of the pathogen-induced modifications of the CW components are still largely unknown, especially at the level of the polysaccharide fraction. To address this significant knowledge gap, we adopted the compatible Pseudomonas syringae-Arabidopsis thaliana system. We found that, despite systemic signaling actuation, Pseudomonas infection leads only to local CW modifications. Furthermore, by utilizing a combination of CW and immune signaling-deficient mutants infected with virulent or non-virulent bacteria, we demonstrated that the pathogen-induced changes in CW polysaccharides depend on the combination of pathogen virulence and the host's ability to mount an immune response. This results in a pathogen-driven accumulation of CW hexoses, such as galactose, and an immune signaling-dependent increase in CW pentoses, mainly arabinose, and xylose. Our analyses of CW changes during disease progression also revealed a distinct spatiotemporal pattern of arabinogalactan protein (AGP) deposition and significant modifications of rhamnogalacturonan sidechains. Furthermore, genetic analyses demonstrated a critical role of AGPs, specifically of the Arabinoxylan Pectin Arabinogalactan Protein1, in limiting pathogen growth. Collectively, our results provide evidence for the actuation of significant remodeling of CW polysaccharides in a compatible host-pathogen interaction, and, by identifying AGPs as critical elements of the CW in plant defense, they pinpoint opportunities to improve plants against diverse pathogens.

Cell- and development-specific degradation controls the levels of mixed-linkage glucan in sorghum leaves.

Mixed-linkage glucan (MLG) is a component of the cell wall (CW) of grasses and is composed of glucose monomers linked by ß-1,3 and ß-1,4 bonds. MLG is believed to have several biological functions, such as the mobilizable storage of carbohydrates and structural support of the CW. The extracellular levels of MLG are largely controlled by rates of synthesis mediated by cellulose synthase-like (CSL) enzymes, and turnover by lichenases. Economically important crops like sorghum accumulate MLG to variable levels during development. While in sorghum, like other grasses, there is one major MLG synthase (CSLF6), the identity of lichenases is yet unknown. To fill this gap, we identified three sorghum lichenases (SbLCH1-3) and characterized them in leaves in relation to the expression of SbCSLF6, and the abundance of MLG and starch. We established that SbLCH1-3 are secreted to the apoplast, consistent with a role of degrading MLG extracellularly. Furthermore, while SbCSLF6 expression was associated with cell development, the SbLCH genes exhibited distinct development-, cell-type-specific and diel-regulated expression. Therefore, our study identifies three functional sorghum MLG lichenases and highlights that MLG accumulation in sorghum leaves is likely controlled by the activity of lichenases that tune MLG levels, possibly to suit distinct cell and developmental needs in planta. These findings have important implications for improving the growth, yield, and composition of sorghum as a feedstock.

Multiple horizontal gene transfer events have shaped plant glycosyl hydrolase diversity and function.

Plant glycosyl hydrolases (GHs) play a crucial role in selectively breaking down carbohydrates and glycoconjugates during various cellular processes, such as reserve mobilization, pathogen defense, and modification/disassembly of the cell wall. In this study, we examined the distribution of GH genes in the Archaeplastida supergroup, which encompasses red algae, glaucophytes, and green plants. We identified that the GH repertoire expanded from a few tens of genes in early archaeplastidians to over 400 genes in modern angiosperms, spanning 40 GH families in land plants. Our findings reveal that major evolutionary transitions were accompanied by significant changes in the GH repertoire. Specifically, we identified at least 23 GH families acquired by green plants through multiple horizontal gene transfer events, primarily from bacteria and fungi. We found a significant shift in the subcellular localization of GH activity during green plant evolution, with a marked increase in extracellular-targeted GH proteins associated with the diversification of plant cell wall polysaccharides and defense mechanisms against pathogens. In conclusion, our study sheds light on the macroevolutionary processes that have shaped the GH repertoire in plants, highlighting the acquisition of GH families through horizontal transfer and the role of GHs in plant adaptation and defense mechanisms.

Biomarkers determining treatment interval of diabetic macular edema after initial resolution by anti-vascular endothelial growth factor.

PURPOSE: To identify predictive factors that help determine the interval of intravitreal anti-vascular endothelial growth factor (anti-VEGF) injection after the initial resolution of diabetic macular edema (DME). METHODS: This retrospective case-control study enrolled treatment-naïve DME patients who had achieved DME resolution after intravitreal anti-VEGF injections. Patients were classified into the recurrence and no-recurrence groups, depending on the development of recurrent DME after deferring intravitreal anti-VEGF injection. The demographics and clinical features, including optical coherence tomography findings, were compared between the two groups. RESULTS: We enrolled 105 eyes. Sixty eyes (57.1%) belonged to the no-recurrence group, and 45 (42.9%), belonged to the recurrence group. The severity of diabetic retinopathy at baseline was related to early DME recurrence (P = 0.009). At the treatment deferring point, the non-recurrence group had both thinner central subfield thickness (289.5 ± 27.2 µm vs. 307.0 ± 38.2 µm, P = 0.011) and thinner central retinal thickness (214.9 ± 41.4 µm vs. 231.8 ± 41.2 µm, P = 0.043) compared to the recurrence group. Intraretinal cyst was observed in 34 eyes (56.7%) in the no-recurrence group and 42 eyes (93.3%) in the recurrence group at the deferring point (P < 0.001). CONCLUSION: A low risk of early DME recurrence is anticipated in the eyes with foveal thinning and no intraretinal cyst when anti-VEGF injection is deferred. These predictive biomarkers can be useful for patient monitoring and determining treatment strategies for DME patients.

Macular hole with epiretinal proliferation: diagnostic value of en-face optical coherence tomography and clinical characteristics.

PURPOSE: To elucidate the clinical features and surgical outcomes of full-thickness macular hole (FTMH) with epiretinal proliferation (EP) diagnosed by both en-face and B-mode optical coherence tomography (OCT). METHOD: This retrospective cohort study classified idiopathic FTMHs into two groups, based on B-scan and en-face OCT imaging: FTMH with EP (EP group) and without EP (non-EP group). The preoperative features, as well as postoperative outcomes up to 12 months, were compared between the two groups. RESULT: Among 318 eyes of idiopathic FTMH that met the inclusion criteria, 59 eyes (18.6%) were in the EP group, and others were in the non-EP group. In 9 eyes (15.3%) out of the EP group, EP was not detected in the preoperative B-mode OCT but was identified through the en-face OCT. Baseline features showed a higher male proportion (47.5% vs. 27.8%, P = 0.005) and a lower incidence of vitreofoveal traction (P < 0.001) in the EP group than in the non-EP group. The EP group showed worse visual recovery than the non-EP group (- 0.23 vs. - 0.41 logarithm of the minimum angle of the resolution at 12 months, P = 0.001). CONCLUSION: The en-face OCT enhances diagnostic accuracy of EP in FTMH eyes, especially in the case with smaller extent of EP. Eyes with FTMH with EP showed a worse visual recovery than FTMH without EP.

RISK OF EXUDATION IN EYES WITH NONEXUDATIVE POLYPOIDAL CHOROIDAL VASCULOPATHY.

PURPOSE: To investigate the characteristics and natural history of treatment-naive nonexudative polypoidal choroidal vasculopathy (PCV) and to determine biomarkers predicting exudative conversion. METHODS: Patients diagnosed with nonexudative PCV based on indocyanine green angiography and optical coherence tomography were included. Incidence of exudative conversion in nonexudative PCV patients and cumulative estimates for overall risk were assessed. Indocyanine green angiography and optical coherence tomography imaging-based features were analyzed to identify risk factors for exudative conversion. RESULTS: The study included 42 eyes of 40 patients with nonexudative PCV. The mean follow-up duration was 54.3 ± 35.5 months. Of the 42 eyes with nonexudative PCV, exudative conversion developed in 23 eyes (54.8%) after 42.2 ± 28.3 months (range, 8-103 months). Kaplan-Meier analysis showed that the exudation-free survival at 5 years after baseline was estimated to be 53.6%. Multivariate regression analysis showed that sequentially increased protrusion of retinal pigment epithelium in the polyp area was a significant risk factor for exudation in nonexudative PCV (odds ratio = 10.16; 95% CI 1.78-57.81; P = 0.01). CONCLUSION: Exudative conversion has been noted in nearly half of the nonexudative PCV cases in 5 years. The progressive protrusion of polypoidal lesions on optical coherence tomography examination may be a significant biomarker for predicting the near-term onset of exudation.

THE IMPACT OF EARLY SURGICAL INTERVENTION ON ANISEIKONIA IN PATIENTS WITH EPIRETINAL MEMBRANE: A Prospective Cohort Study.

PURPOSE: To investigate the efficacy of early surgical intervention in ameliorating aniseikonia among patients with epiretinal membrane. METHODS: This prospective cohort study enrolled patients who underwent surgery for epiretinal membrane. Patients were divided into early (symptom onset within 1 year) and late (symptom onset ≥1 year) treatment groups. Changes in aniseikonia, best-corrected visual acuity, and tangential retinal displacement were assessed and compared at 6 and 12 months postoperatively. RESULTS: Of the 56 patients, 30 (53.6%) belonged to the early treatment group and 26 (46.4%) to the late treatment group. The early treatment group demonstrated a significant reduction in aniseikonia score at 6- and 12-month follow-up visits (-1.10 ± 1.50 [P = 0.002] and -1.18 ± 1.79 [P = 0.003], respectively); however, no improvement was observed in the late treatment group (0.98 ± 4.62 [P = 0.310] and 1.52 ± 4.35 [P = 0.124], respectively). The early treatment group showed larger tangential retinal displacement at the 12-month postoperative follow-up visit. In addition, the amount of tangential retinal displacement was associated with postoperative changes in aniseikonia. CONCLUSION: Early surgical intervention is helpful in improving aniseikonia in patients with epiretinal membrane. The degree of recovery in inner retinal displacement was associated with the improvement of aniseikonia.

Disruption of Brachypodium lichenase alters metabolism of mixed-linkage glucan and starch.

Mixed-linkage glucan, which is widely distributed in grasses, is a polysaccharide highly abundant in cell walls of grass endosperm and young vegetative tissues. Lichenases are enzymes that hydrolyze mixed-linkage glucan first identified in mixed-linkage glucan-rich lichens. In this study, we identify a gene encoding a lichenase we name Brachypodium distachyon LICHENASE 1 (BdLCH1), which is highly expressed in the endosperm of germinating seeds and coleoptiles and at lower amounts in mature shoots. RNA in situ hybridization showed that BdLCH1 is primarily expressed in chlorenchyma cells of mature leaves and internodes. Disruption of BdLCH1 resulted in an eight-fold increase in mixed-linkage glucan content in senesced leaves. Consistent with the in situ hybridization data, immunolocalization results showed that mixed-linkage glucan was not removed in chlorenchyma cells of lch1 mutants as it was in wild type and implicate the BdLCH1 enzyme in removing mixed-linkage glucan in chlorenchyma cells in mature vegetative tissues. We also show that mixed-linkage glucan accumulation in lch1 mutants was resistant to dark-induced degradation, and 8-week-old lch1 plants showed a faster rate of starch breakdown than wild type in darkness. Our results suggest a role for BdLCH1 in modifying the cell wall to support highly metabolically active cells.

Impact of Age-Related Macular Degeneration and Related Visual Disability on the Risk of Depression: A Nationwide Cohort Study.

PURPOSE: To evaluate the prospective association of age-related macular degeneration (AMD) and related visual disability (VD) with the risk of depression. DESIGN: This nationwide population-based cohort study used authorized clinical data provided by the Korean National Health Insurance Service. PARTICIPANTS: A total of 3 599 589 individuals older than 50 years participated in the Korean National Health Screening Program in 2009. METHODS: Age-related macular degeneration diagnosis and the presence of accompanying VD were verified using diagnostic codes and disability registration data. Data on covariates, including age, sex, income level, residential area, systemic comorbidities, and behavioral factors, were collected from health screening results and claims data. Patients were followed up until December 2019, and incident cases of depression were identified using registered diagnostic codes. The prospective association of AMD and related VD with new-onset depression was investigated using the multivariable-adjusted Cox proportional hazard model. MAIN OUTCOME MEASURES: Hazard ratios and 95% confidence intervals (CIs) for depression development according to the presence of AMD and VD. RESULTS: During an average follow-up period of 8.52 years, 1 037 088 patients received new diagnoses of depression. Patients with previous diagnoses of AMD showed a greater risk of new-onset depression, with a hazard ratio of 1.15 (95% CI, 1.13-1.17) compared with the control group in the fully adjusted model. Patients with AMD and accompanying VD showed a further increased risk of depression, with a hazard ratio of 1.23 (95% CI, 1.16-1.30). CONCLUSIONS: Individuals with a diagnosis of AMD have a higher risk of depression developing in the future. The risk of depression is increased further in patients with AMD who demonstrate VD. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.