Neuroprotective effects of apigenin on retinal ganglion cells in ischemia/reperfusion: modulating mitochondrial dynamics in in vivo and in vitro models.

BACKGROUND: Retinal ischemia/reperfusion (RIR) is implicated in various forms of optic neuropathies, yet effective treatments are lacking. RIR leads to the death of retinal ganglion cells (RGCs) and subsequent vision loss, posing detrimental effects on both physical and mental health. Apigenin (API), derived from a wide range of sources, has been reported to exert protective effects against ischemia/reperfusion injuries in various organs, such as the brain, kidney, myocardium, and liver. In this study, we investigated the protective effect of API and its underlying mechanisms on RGC degeneration induced by retinal ischemia/reperfusion (RIR). METHODS: An in vivo model was induced by anterior chamber perfusion following intravitreal injection of API one day prior to the procedure. Meanwhile, an in vitro model was established through 1% oxygen and glucose deprivation. The neuroprotective effects of API were evaluated using H&E staining, spectral-domain optical coherence tomography (SD-OCT), Fluoro-Gold retrograde labeling, and Photopic negative response (PhNR). Furthermore, transmission electron microscopy (TEM) was employed to observe mitochondrial crista morphology and integrity. To elucidate the underlying mechanisms of API, the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, flow cytometry assay, western blot, cell counting kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) assay, JC-1 kit assay, dichlorofluorescein-diacetate (DCFH-DA) assay, as well as TMRE and Mito-tracker staining were conducted. RESULTS: API treatment protected retinal inner plexiform layer (IPL) and ganglion cell complex (GCC), and improved the function of retinal ganglion cells (RGCs). Additionally, API reduced RGC apoptosis and decreased lactate dehydrogenase (LDH) release by upregulating Bcl-2 and Bcl-xL expression, while downregulating Bax and cleaved caspase-3 expression. Furthermore, API increased mitochondrial membrane potential (MMP) and decreased extracellular reactive oxygen species (ROS) production. These effects were achieved by enhancing mitochondrial function, restoring mitochondrial cristae morphology and integrity, and regulating the expression of OPA1, MFN2, and DRP1, thereby regulating mitochondrial dynamics involving fusion and fission. CONCLUSION: API protects RGCs against RIR injury by modulating mitochondrial dynamics, promoting mitochondrial fusion and fission.

Semipinacol Rearrangement of Iododifluorohomoallyl Alcohols and Its Application in the Allylic C-H Esterification Reactions.

We herein present a study on the Ag(I)-mediated semipinacol rearrangement of iododifluorohomoallyl alcohols, the resulting allylic difluoromethyl ketones underwent oxidative allylic C-H esterification under palladium catalysis in the absence of external ligand. This process yielded a range of difluoromethyl ketones derived from allyl esters in a single operation. The reaction features broad scope of o-nitrobenzoic acids and homoallylic iododifluoroalcohols affording the targeted molecules in synthetically useful yields. Control experiments illustrated that the silver salt acted as not only a Lewis acid to promote the cleavage of a C-I bond and furnish the semipinacol rearrangement but also a co-oxidant in the catalytic cycle for the allylic C-H esterification.

Integrating convolution and self-attention improves language model of human genome for interpreting non-coding regions at base-resolution.

Interpretation of non-coding genome remains an unsolved challenge in human genetics due to impracticality of exhaustively annotating biochemically active elements in all conditions. Deep learning based computational approaches emerge recently to help interpret non-coding regions. Here, we present LOGO (Language of Genome), a self-attention based contextualized pre-trained language model containing only two self-attention layers with 1 million parameters as a substantially light architecture that applies self-supervision techniques to learn bidirectional representations of the unlabelled human reference genome. LOGO is then fine-tuned for sequence labelling task, and further extended to variant prioritization task via a special input encoding scheme of alternative alleles followed by adding a convolutional module. Experiments show that LOGO achieves 15% absolute improvement for promoter identification and up to 4.5% absolute improvement for enhancer-promoter interaction prediction. LOGO exhibits state-of-the-art multi-task predictive power on thousands of chromatin features with only 3% parameterization benchmarking against the fully supervised model, DeepSEA and 1% parameterization against a recent BERT-based DNA language model. For allelic-effect prediction, locality introduced by one dimensional convolution shows improved sensitivity and specificity for prioritizing non-coding variants associated with human diseases. In addition, we apply LOGO to interpret type 2 diabetes (T2D) GWAS signals and infer underlying regulatory mechanisms. We make a conceptual analogy between natural language and human genome and demonstrate LOGO is an accurate, fast, scalable, and robust framework to interpret non-coding regions for global sequence labeling as well as for variant prioritization at base-resolution.

Constitutive signal bias mediated by the human GHRHR splice variant 1.

Alternative splicing of G protein-coupled receptors has been observed, but their functions are largely unknown. Here, we report that a splice variant (SV1) of the human growth hormone-releasing hormone receptor (GHRHR) is capable of transducing biased signal. Differing only at the receptor N terminus, GHRHR predominantly activates Gs while SV1 selectively couples to ß-arrestins. Based on the cryogenic electron microscopy structures of SV1 in the apo state or GHRH-bound state in complex with the Gs protein, molecular dynamics simulations reveal that the N termini of GHRHR and SV1 differentiate the downstream signaling pathways, Gs versus ß-arrestins. As suggested by mutagenesis and functional studies, it appears that GHRH-elicited signal bias toward ß-arrestin recruitment is constitutively mediated by SV1. The level of SV1 expression in prostate cancer cells is also positively correlated with ERK1/2 phosphorylation but negatively correlated with cAMP response. Our findings imply that constitutive signal bias may be a mechanism that ensures cancer cell proliferation.

Profiling flavor characteristics of cold brew coffee with GC-MS, electronic nose and tongue: effect of roasting degrees and freeze-drying.

BACKGROUND: Roasting is an important process in the formation of coffee flavor characteristics, which determines the quality of coffee and consumer acceptance. However, the influence of roasting degree on the flavor characteristics of cold brew coffee has not been fully described. RESULTS: In the present study, the flavor characteristics of cold brew coffee with different roasting degrees were compared in detail by using chromatographic and electronic sensory approaches, and the flavor changes induced by freeze-drying were investigated. Pyrazine and heterocyclic compounds were the main aroma compounds in coffee, and gradually dominated with the increase of roasting. Pyridine was consistently present in cold brew coffees of different roasting degrees and showed significant gradient of quantity accumulation. Aroma compounds such as pyrazine, linalool and furfuryl acetate were the main contributors to coffee roasting, floral and fruity flavor. Freeze-drying preserved the fruity and floral aromas of medium-roasted cold brew coffee, whereas reducing the bitterness, astringency and acidity properties that are off-putting to consumers. CONCLUSION: The higher consumer acceptance and enjoyment in medium roast cold brew coffee may be related to its stronger floral and fruity aroma. The aroma profile qualities of freeze-drying processed medium roasted cold brewed coffee were more dominant and more suitable for freeze-drying processing than medium dark roasting. Application of freeze-drying for cold brew coffee will promote the convenience of drinking. The present study provides valuable technical guidance in improving the flavor and quality of cold brew coffee, and also promotes its commercialization process. © 2024 Society of Chemical Industry.

Alteration of volatile profiles in heat-sterilized cloudy muskmelon juice as affected by pectin fractions.

BACKGROUND: Flavor is considered as a key quality attribute of fruit juice affecting consumer acceptance. During processing, the flavor loss of cloudy juice always occurs due to the variations of juice cloud particles. Pectin, a major component of cloud particles, plays an important role in cloud stability. In this work, we focused on the effects of variation of three pectin fractions caused by gentle centrifugation and clarification on the physicochemical properties, volatile content and sensory profile of heat-sterilized muskmelon cloudy juice. RESULTS: Centrifugation treatment reduced the total soluble solids and viscosity of cloudy juice and increased cloud stability. With centrifugation increased, the contents of most monosaccharides in the three pectin fractions were reduced. Most aroma-active aldehydes and alcohols, such as (2E,6Z)-nonadienal, 1-octen-3-ol and (E)-non-2-enal, after gentle centrifugation and clarification, were maintained, but most esters were decreased. The volatile compositions were highly related to the three pectin fractions. The addition of chelator-soluble pectin and sodium carbonate-soluble pectin could decrease the formation of dimethyl trisulfide and dimethyl disulfide in clarified juice, thereby improving the sensory profile. CONCLUSION: The results suggested that endogenous chelator-soluble pectin and sodium carbonate-soluble pectin can be used in heat-sterilized fruit juice to improve flavor quality, with an emphasis on a significant reduction in volatile sulfur compounds. © 2023 Society of Chemical Industry.

Strategy for anthocyanins production: From efficient green extraction to novel microbial biosynthesis.

Anthocyanins are widely distributed in nature and exhibit brilliant colors and multiple health-promoting effects; therefore, they are extensively incorporated into foods, pharmaceuticals, and cosmetic industries. Anthocyanins have been traditionally produced by plant extraction, which is characterized by high expenditure, low production rates, and rather complex processes, and hence cannot meet the increasing market demand. In addition, the emerging environmental issues resulting from traditional solvent extraction technologies necessitate a more efficient and eco-friendly alternative strategy for producing anthocyanins. This review summarizes the efficient approach for green extraction and introduces a novel strategy for microbial biosynthesis of anthocyanins, emphasizing the technological changes in production.

Mitochondria-associated endoplasmic reticulum membranes dysfunction contributes to PARP-1-dependent cell death under oxidative stress in retinal precursor cells.

Persistent poly (ADP-ribose) polymerase 1 (PARP-1) activation has proven detrimental and can lead to PARP-1-dependent cell death. Mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) serve as essential hubs for many biological pathways, such as autophagy and mitochondria fission and fusion. This study aimed to alleviate the effects of hydrogen peroxide (H2 O2 )-induced persistent PARP-1 activation and MAM dysregulation by the usage of a PARP-1 inhibitor. Results showed that receptor-interacting protein kinase (RIPK) 1 inhibitor (necrostatin-1) and PARP-1 inhibitor (olaparib) protected retinal precursor cells from H2 O2 -induced death, while a pan-caspase inhibitor (Z-VAD-FMK) failed to protect R28 cells. Olaparib also alleviated H2 O2 -induced MAM dysregulation, as evidenced by decreased VDAC1/ITPR3 interactions and reduced mitochondrial membrane potential collapse. Additionally, olaparib also inhibited H2 O2 -induced autophagy. Inhibiting autophagic flux increased MAM signaling under both normal and oxidative conditions. Furthermore, H2 O2 treatment caused a reduction in the protein level of mitofusin-2 (MFN2) in a dose- and time-dependent manner. Mfn2 knockdown was found to further magnify MAM dysregulation and mitochondrial dysfunction under normal and oxidative conditions. Mfn2 overexpression surprisingly enhanced H2 O2 -induced MAM signaling and failed to rescue H2 O2 -induced mitochondrial dysfunction. These results indicate that MAMs probably serve as a membrane source for oxidative stress-associated autophagy. MAM dysregulation also contributed to H2 O2 -induced PARP-1-dependent cell death. However, more studies are required to decipher the link between the modulation of Mfn2 expression, changes in MAM integrity, and alterations in mitochondrial performances.

OUTER RETINAL TUBULATION IN BIETTI CRYSTALLINE DYSTROPHY ASSOCIATED WITH THE RETINAL PIGMENT EPITHELIUM ATROPHY.

PURPOSE: To determine the prognostic value of outer retinal tubulation (ORT) in the eyes of a Chinese cohort with Bietti crystalline dystrophy (BCD). METHODS: This retrospective, multicenter cohort study enrolled 42 patients with clinically and genetically diagnosed BCD. Eighty eyes with good-quality images of spectral domain optical coherence tomography were included. Demographic details and clinical data were collected. The characteristics of ORT, including prevalence, location, and morphologic characteristics were analyzed. RESULTS: Forty-two patients with BCD harbored potentially CYP4V2 disease-causing mutations. The mutation spectrum comprised 17 unique variants, 9 of which were novel. Fifty-two of these 80 eyes demonstrated evidence of ORT. The incidence of ORT is significantly higher in Stage 2 than other stages ( P < 0.001). ORT was mainly bilateral and located at the margin of the atrophic area of retinal pigment epithelium (RPE), and dynamically changed with the progressive RPE atrophy. The process of RPE atrophy was slower in eyes with ORT ( P = 0.017), with significantly longer intact RPE width in Stage 3 ( P = 0.024). Eyes with ORT had slower vision loss than eyes without ORT ( P = 0.044). CONCLUSION: ORT may be a sign of the onset of RPE atrophy in early-stage BCD and may suggest less risk of rapid progression in late-stage BCD.

Volume-accumulated reflectivity of the outer retina (integral) on spectral domain optical coherence tomography as a predictor of cone cell density: a pilot study.

BACKGROUND: The study aims to investigate the relationship between the volume-accumulated reflectivity (termed "integral") on spectral domain optical coherence tomography (SD-OCT) and cone density on adaptive optics (AO) imaging. METHODS: In this cross-sectional study, both eyes of 32 healthy subjects and 5 patients with inherited retinal diseases (IRD) were studied. The parameter, integral, was defined as the volume-accumulated reflectivity values in a selected region on OCT images; integrals of the ellipsoid zone (EZ) and interdigitation zone (IZ) were measured at 2°, 3°, 4°, 5°and 6° eccentricity along the four meridians on fovea-centered OCT B-scans. Cone density in the same region was measured using a flood illumination adaptive optics camera RTX1. RESULTS: Integrals of EZ, IZ and cone density shared similar distribution patterns. Integral of the IZ was better correlated with cone density in both healthy people (r = 0.968, p < 0.001) and those with IRD (r = 0.823, p < 0.001) than direct measurements of reflectivity on OCT images. A strong correlation was found between best corrected visual acuity (BCVA) and cone density at 2° eccentricity (r = -0.857, p = 0.002). BCVA was also correlated with the integral of the IZ at the foveola (r = -0.746, p = 0.013) and fovea (r = -0.822, p = 0.004). CONCLUSIONS: The new parameter "integral" of the photoreceptor outer segment measured from SD-OCT was noted to correlate with cone density and visual function in this pilot study.

Enhancement effect of odor and multi-sensory superposition on sweetness.

The impact of sugary foods on public health has contributed to the development of low-sugar and sugar-substituted products, and sugar reduction has become a major challenge for the food industry. There is growing empirical evidence that odor can enhance the perception of sweetness without increasing the caloric load. This current review summarizes the researches on odor-induced sweetness enhancement published in recent years and discusses the mechanisms and influencing factors of odor-sweetness interactions. In addition, by combing existing studies, this paper also summarizes the research methods and strategies to investigate odor-induced sweetness enhancement. Finally, the feasibility of synergistic enhancement of sweetness through the superposition of odor with other senses (texture, visual, etc.) is also discussed and analyzed. In conclusion, odor-induced sweetness enhancement may present an alternative or complementary approach for developing foods with less sugar.

CXC- receptor 2 promotes extracellular matrix production and attenuates migration in peripapillary human scleral fibroblasts under mechanical strain.

As the main loading-bearing tissue of eye, sclera exerts an important role in the pathophysiology of glaucoma. Intraocular pressure (IOP) generates mechanical strain on sclera. Recent studies have demonstrated that sclera, especially the peripapillary sclera, undergoes complicated remodelling under the mechanical strain. However, the mechanisms of the hypertensive scleral remodelling in human eyes remained uncertain. In this study, peripapillary human scleral fibroblasts (ppHSFs) were applied cyclic mechanical strain by Flexcell-5000™ tension system. We found that CXC- ligands and CXCR2 were differentially expressed after strain. Increased cell proliferation and inhibited cell motility were observed when CXCR2 was upregulated under the strain, whereas cell proliferation and motility did not have a significant change when CXCR2 was knocked down. CXCR2 could facilitate cell proliferation ability, modulate the mRNA and protein expressions of type I collagen and matrix metalloproteinase 2 via JAK1/2-STAT3 signalling pathway. In addition, CXCR2 might inhibit cell migration via FAK/MLC2 pathway. Taken together, CXCR2 regulated protein production and affected cell behaviours of ppHSFs. It might be a potential therapeutic target for the hypertensive scleral remodelling.

Nobiletin protects retinal ganglion cells in models of ocular hypertension in vivo and hypoxia in vitro.

Glaucoma, a common cause of blindness, is characterized by the progressive loss of retinal ganglion cells (RGCs). Growing evidence suggests that nobiletin (NOB) is a promising neuroprotective drug; however, its effects on glaucomatous neurodegeneration remain unknown. Using rat models of microbead occlusion in vivo and primary RGCs model of hypoxia in vitro, we first demonstrate that NOB reduces RGC apoptosis by a TUNEL assay, Hoechst 33342 staining and FluoroGold (FG) retrograde labeling. This effect does not depend on intraocular pressure (IOP) lowering. Additionally, NOB partially restored the functional and structural damage of inner retinas, attenuated Müller glial activation and oxidative stress caused by ocular hypertension. At 2 weeks after IOP elevation, NOB further enhanced Nrf2/HO-1 pathway in RGCs to withstand the cumulative damage of ocular hypertension. With the administration of HO-1 inhibitor tin-protoporphyrin IX (SnPP), the protective effect of NOB was attenuated. Overall, these results indicate that NOB exerts an outstanding neuroprotective effect on RGCs of glaucomatous neurodegeneration. Besides, interventions to enhance activation of Nrf2/HO-1 pathway can slow the loss of RGCs and are viable therapies for glaucoma.

Regulation of mitophagy by metformin improves the structure and function of retinal ganglion cells following excitotoxicity-induced retinal injury.

Excitotoxicity-induced retinal neuronal death is characterized by the progressive retinal ganglion cell (RGC) apoptosis. Strategies are needed to reduce neurodegeneration. Recent investigations have indicated the potential effects of metformin on multiple systems, especially in the networks. However, it also remains unclear whether mitophagy contributes to the neuroprotective effect of metformin on the retina. In this study, excitotoxicity-induced retinal injury models were constructed. In vitro, R28 cells were treated with calcium ionophore and metformin/phosphate-buffer saline (PBS). Cell viability, lactate dehydrogenase release, and the cellular apoptosis rate were assessed. In vivo, rats received intravitreal injection of N-methyl-D-aspartate and metformin/PBS. Comprehensive examinations including retrograde fluorescent gold labelling, Nissl's staining, full-field electroretinography, photopic negative response, optic coherence tomography and retinal imaging, transmission electron microscopy, western blotting, and quantitative polymerase chain reaction were conducted during the observation period. The viability of R28 cells was significantly increased in the metformin-treated group compared with the negative control group, while, the release of lactate dehydrogenase and R28 cell apoptosis showed a significant decrease. In vivo, metformin treatment significantly increased the number of surviving RGCs, the b/NR wave amplitude and the thickness of the inner retina but had no obvious adverse effects on the fundus. In the metformin-treated group, the morphology and number of mitochondria were better preserved, as observed for RGCs; mitochondrial autophagosomes were located in RGCs, as indicated by transmission electron microscopy; and the expression of mitophagy-related genes and proteins presented was significant regulated. These data indicated that the regulation of mitophagy by metformin improved the structure and function of RGCs.

Taurine protects R28 cells from hypoxia/re-oxygenation-induced damage via regulation of mitochondrial energy metabolism.

Oxidative-induced damage and hypoxia/re-oxygenation (H/R) injury are common causes of irreversible visual impairment. The goals of this study were to explore the effects of taurine on R28 cells under the two damage models and the underlying mechanisms. Low doses of taurine supplementation promoted cell viability, mitochondrial membrane potential (MMP), SOD levels, ATP contents and attenuated cytotoxicity and intracellular ROS generation of the R28 cells under the two kinds of damage. The expression level of GTPBP3, a mitochondrial-tRNA (mt-tRNA) modification enzyme that catalyzes the taurine involved modification, was decreased under the two damage and taurine could reverse the reduction. After knocking down GTPBP3, the R28 cells become vulnerable to damage. The viability, cytotoxicity, MMP and intracellular ROS level of knockdown cells changed more obviously under the H/R injury than those of control cell. We also found that knockdown of GTPBP3 significantly decreased mitochondrial energy metabolism by measuring the oxidative respiration rate by the Seahorse XFe24 extracellular flux analyzer. The protection of low doses of taurine disappeared on knockdown R28 cells, indicating that GTPBP3 is crucial in the protection mechanisms of taurine. However, the impacts of the reduction of GTPBP3 level can be reversed by relatively high doses of taurine, implying the protection effects of taurine were dose-dependent, and there were more complicated mechanisms remain to be explored. This study explored a new mechanism of the neuroprotective effects of taurine, which depend on the GTPBP3-mediated taurine modification of mt-tRNAs and the promotion of mitochondrial energy metabolism.

Nobiletin Alleviates Astrocyte Activation and Oxidative Stress Induced by Hypoxia In Vitro.

Increasing evidence indicates that nobiletin (NOB) is a promising neuroprotective agent. Astrocyte activation plays a key role in neurodegenerative disorders. Thus, this study aims to investigate the effects of NOB on astrocyte activation and the potential mechanisms. In this study, astrocytes were exposed to hypoxia injury for 24 h to induce activation in vitro. Glial fibrillary acidic protein (GFAP) was chosen as a marker of astrocyte activation. To evaluate the effects of NOB on the migration of activated astrocytes, we used a scratch wound healing assay and Transwell migration assay. In addition, the levels of reactive oxygen species (ROS), malondialdehyde (MDA), mitochondrial membrane potential, Nrf2 and HO-1 were measured to investigate the mechanisms of NOB in the activation of astrocytes. We found that NOB alleviated astrocyte activation and decreased GFAP expression during hypoxia. Simultaneously, NOB alleviated the migration of astrocytes induced by hypoxia. With NOB treatment, hypoxia-induced oxidative stress was partially reversed, including reducing the production of ROS and MDA. Furthermore, NOB significantly improved the mitochondrial dysfunction in activated astrocytes. Finally, NOB promoted Nrf2 nuclear translocation and HO-1 expression in response to continuous oxidative damage. Our study indicates, for the first time, that NOB alleviates the activation of astrocytes induced by hypoxia in vitro, in part by ameliorating oxidative stress and mitochondrial dysfunction. This provides new insights into the neuroprotective effects of NOB.

Production of Marinated Chinese Lotus Root Slices Using High-Pressure Processing as an Alternative to Traditional Thermal-and-Soaking Procedure.

Marinated vegetables are traditional cold dishes with a long history and special flavor in the Chinese deli market. However, the traditional thermal-and-soaking (TS) procedure often results in unreproducible flavor quality properties of marinated vegetables and waste of brine and time in production. A novel green and sustainable technique, high-pressure processing (HPP), has caught the attention of the food industry. In this study, the effects of HPP and TS treatment on the visual, flavor, textural, and microbiological qualities of Chinese marinated lotus root slices were investigated. Compared to the TS products, lighter color, more varieties of volatile compounds, and crunchier texture were detected in the HPP products. Throughout the 4 °C, 25 °C, and 45 °C shelf life challenges, the HPP products retained their original color and crunchiness better than the TS ones, whereas no significant differences were found in total viable counts (TVCs) in the first half of the shelf lives. The Arrhenius model under the first-order reaction of TVC deterioration showed a good fit to the shelf life of the HPP marinated lotus root slices. This study demonstrates that HPP may assist in making the best use of brine in a more time-efficient manner to improve the visual, flavor, and textural quality of traditional Chinese marinated lotus root slices.

Nicotinamide ameliorates energy deficiency and improves retinal function in Cav-1-/- mice.

Caveolin-1(Cav-1) is involved in lipid metabolism and energy homeostasis, which is important for the energetically demanding retina. Although retinal function deficits were noted in Cav-1 knockout (Cav-1-/- ) mice, the underlying causes remain largely unknown. Here, we investigate if the disruption in energy homeostasis presents a potential mechanism for retinal function deficits in Cav-1-/- retina and if it can be ameliorated by nicotinamide (NAM). In this study, NAM was administrated orally for 2 weeks in Cav-1-/- mice before experiments. Oxidative lipidomics was conducted to detect the oxylipin changes, the retinal energy flux was measured by seahorse assay, and the retinal function was assessed by electroretinogram (ERG). Cav-1 deficiency induced the dysregulation of oxidative lipidomics and reduction in energy consumption/production in the retina by decreasing Na+ /K+ -ATPase, oxidative phosphorylation CII, cytochrome c, and oxygen consumption rate (OCR). A decrease in Sirt1 was also detected. Therapeutic administration of NAM significantly increased Sirt1 expression and improved energy deficiency by increasing Na+ /K+ -ATPase, cytochrome c, and OCR. The dysregulation of oxidative lipidomics was partially recovered, and the retinal function was improved as assessed by ERG compared to Cav-1-/- mice. Our study demonstrated the dysregulation of oxidative lipidomics in Cav-1-/- retina and established a link between energy deficiency and retinal function deficits in Cav-1-/- mice. Administration of NAM ameliorated energy deficiency, increased the expression of Sirt1, and improved retinal function, which presents a potential therapeutic strategy for Cav-1 deficiency-induced retinal function deficits.

TRPV4-induced Müller cell gliosis and TNF-α elevation-mediated retinal ganglion cell apoptosis in glaucomatous rats via JAK2/STAT3/NF-κB pathway.

BACKGROUND: Glaucoma, the leading cause of irreversible blindness worldwide, is a type of retinal disease characterized by the selective death of retinal ganglion cells (RGCs). However, the pathogenesis of glaucoma has not been fully elucidated. Transient receptor potential vanilloid 4 (TRPV4) is a pressure-sensitive and calcium-permeable cation channel. TRPV4 is widely distributed in the retina and its sustained activation leads to RGC death; indicating that TRPV4 may be a possible target for glaucoma treatment. Here, we investigated the effects of TRPV4 on RGC apoptosis in a rat model of chronic ocular hypertension (COH), then examined the mechanism underlying these effects. METHODS: The COH model was established by injection of micro-magnetic beads into the anterior chamber of adult male rats. The expression levels of TRPV4, glial fibrillary acidic protein, and inflammatory factors were assessed by immunohistochemistry and immunoblotting. RGC apoptosis and visual dysfunction were evaluated by TUNEL assay and photopic negative response. Functional expression of TRPV4 was examined by electrophysiology and calcium imaging. Real-time polymerase chain reaction and immunoblotting were employed to investigate the molecular mechanism underlying the effects of TRPV4 on tumor necrosis factor-α (TNF-α) release. RESULTS: We found that TRPV4 played an essential role in glaucoma, such that high levels of TRPV4 expression were associated with elevated intraocular pressure. Furthermore, TRPV4 activation was involved in glaucoma-induced RGC apoptosis and RGC-related reductions in visual function. Mechanistic investigation demonstrated that TRPV4 activation led to enhanced Müller cell gliosis and TNF-α release via the JAK2/STAT3/NF-kB pathway, while TRPV4 inhibition could reverse these effects. Finally, TRPV4 activation could lead to elevated expression of TNF receptor 1 in RGCs, while inhibition of TNF-α could reduce TRPV4-mediated RGC apoptosis. CONCLUSIONS: TRPV4 activation induces Müller cell gliosis and TNF-α elevation via the JAK2/STAT3/NF-κB pathway, which may exacerbate RGC apoptosis in glaucoma; these results suggest that TRPV4 can serve as a therapeutic target in glaucoma treatment.

High expression of SARS-CoV-2 entry factors in human conjunctival goblet cells.

The angiotensin-converting enzyme 2 (ACE2) receptor has been proved for SARS-CoV-2 cell entry after auxiliary cellular protease priming by transmembrane protease serine 2 (TMPRSS2), but the co-effect of this molecular mechanism was unknown. Here, single-cell sequencing was performed with human conjunctiva and the results have shown that ACE2 and TMPRSS2 were highly co-expressed in the goblet cells with genes involved in immunity process. This identification of conjunctival cell types which are permissive to virus entry would help to understand the process by which SARS-CoV-2 infection was established. These finding might be suggestive for COVID-19 control and protection.