Biology subjects

Qi, X.

Publications and source records attributed to Qi, X..

At least 73 records · Page 4Linked to original sources

bioRxiv2023

Linking root-associated fungal and bacterial functions to root economics

Tree roots form symbioses with soil microbes to acquire nutrients, but the relationships between root nutrient acquisition strategies and microbial community composition remain poorly understood. Here, we measured root traits and root-associated fungal and bacterial guilds in 336 trees of 52 species from a subtropical forest. We found a fungal gradient from ectomycorrhizal to saprotrophic dominance, which corresponded with a shift from organic to mineral nutrient economics. This fungal gradient was aligned with the increase of root nitrogen concentration, suggesting a linkage from simple root trait to fungal-mediated carbon-nutrient cycling. We also found that the functional composition of fungal and bacterial communities was closely correlated with host root-zone pH, which often varied among coexisting trees. Root-zone pH was independent of the common root traits, underpinning a potential new gradient in the root trait space. Our findings integrate microbial functions into the root economics framework, thereby advancing the understanding of diversity of nutrient acquisition strategies across forest trees.

ecology↗

bioRxiv2023

Exploring Temporal and Sex-Linked Dysregulation in Alzheimer's Disease Phospho-Proteome

This study aims to characterize dysregulation of phosphorylation for the 5XFAD mouse model of Alzheimers disease (AD). Employing global phosphoproteome measurements, we analyze temporal (3, 6, 9 months) and sex-dependent effects on mouse hippocampus tissue to unveil molecular signatures associated with AD initiation and progression. Our results indicate 1.9 to 4.4 times higher phosphorylation prevalence compared to protein expression across all time points, with approximately 4.5 times greater prevalence in females compared to males at 3 and 9 months. Moreover, our findings reveal consistent phosphorylation of known AD biomarkers APOE and GFAP in 5XFAD mice, alongside novel candidates BIG3, CLCN6 and STX7, suggesting their potential as biomarkers for AD pathology. In addition, we identify PDK1 as a significantly dysregulated kinase at 9 months in females, and the regulation of gap junction activity as a key pathway associated with Alzheimers disease across all time points. AD-Xplorer, the interactive browser of our dataset, enables exploration of AD-related changes in phosphorylation, protein expression, kinase activities, and pathways. AD-Xplorer aids in biomarker discovery and therapeutic target identification, emphasizing temporal and sex-specific nature of significant phosphoproteomic signatures. Available at: https://yilmazs.shinyapps.io/ADXplorer HighlightsO_LIPhosphorylation-level dysregulation surpasses protein expression C_LIO_LIHigher phospho-dysregulation in females, starting as early as 3-month time point C_LIO_LINovel candidates BIG3, CLCN6, and STX7 exhibit consistent phospho-dysregulation C_LIO_LIDeveloped AD-Xplorer: Online tool to explore Alzheimers disease phospho-proteome C_LI In BriefThis study investigates dysregulation of phospho-proteome in an Alzheimers disease (AD) mouse model, identifying consistent phosphorylation of established AD biomarkers APOE and GFAP, along with novel candidate biomarkers BIG3, CLCN6, and STX7. In addition, the study observes significant PDK1 dysregulation at 9 months, particularly in females. AD-Xplorer, our interactive tool for exploring temporal and sex-linked phosphorylation changes, protein expression, kinase activities, and pathway enrichment, empowers researchers to gain deeper insights into AD mechanisms and uncover novel biomarkers and therapeutic targets.

neuroscience↗

bioRxiv2023

Quantification of glutathione with high throughput live-cell imaging

Reduction oxidation (redox) reactions are central in life and altered redox state is associated with a spectrum of human diseases. Glutathione (GSH) is the most abundant antioxidant in eukaryotic cells and plays critical roles in maintaining redox homeostasis. Thus, measuring intracellular GSH level is an important method to assess the redox state of organism. The currently available GSH probes are based on irreversible chemical reactions with glutathione and cant monitor the real-time glutathione dynamics. Our group developed the first reversible reaction based fluorescent probe for glutathione, which can measure glutathione levels at high resolution using a confocal microscope and in the bulk scale with a flow cytometry. Most importantly it can quantitatively monitor the real-time GSH dynamics in living cells. Using the 2nd generation of GSH probe, RealThiol (RT), this study measured the GSH level in living Hela cells after treatment with varying concentrations of DL-Buthionine sulfoximine (BSO) which inhibits GSH synthesis, using a high throughput imaging system, Cytation 5 cell imaging reader. The results revealed that GSH probe RT at the concentration of 2.0 {micro}M accurately monitored the BSO treatment effect on GSH level in the Hela cells. The present results demonstrated that the GSH probe RT is sensitive and precise in GSH measurement in living cells at a high throughput imaging platform and has the potential to be applied to any cell lines.

biochemistry↗

bioRxiv2023

EMDiffuse: a diffusion-based deep learning method augmenting ultrastructural imaging and volume electron microscopy

Electron microscopy (EM) revolutionized the way to visualize cellular ultrastructure. Volume EM (vEM) has further broadened its three-dimensional nanoscale imaging capacity. However, intrinsic trade-offs between imaging speed and quality of EM restrict the attainable imaging area and volume. Isotropic imaging with vEM for large biological volumes remains unachievable. Here we developed EMDiffuse, a suite of algorithms designed to enhance EM and vEM capabilities, leveraging the cutting-edge image generation diffusion model. EMDiffuse demonstrates outstanding denoising and super-resolution performance, generates realistic predictions without unwarranted smoothness, improves predictions resolution by [~]30%, and exhibits excellent transferability by taking only one pair of images to fine-tune. EMDiffuse also pioneers the isotropic vEM reconstruction task, generating isotropic volume similar to that obtained using advanced FIB-SEM even in the absence of isotropic training data. We demonstrated the robustness of EMDiffuse by generating isotropic volumes from six public datasets obtained from different vEM techniques and instruments. The generated isotropic volume enables accurate organelle reconstruction, making 3D nanoscale ultrastructure analysis faster and more accessible and extending such capability to larger volumes. More importantly, EMDiffuse features self-assessment functionalities and guarantees reliable predictions for all tasks. We envision EMDiffuse to pave the way for more in-depth investigations into the intricate subcellular nanoscale structures within large areas and volumes of biological systems.

cell biology↗

bioRxiv2023

Mechanical Force Imprints Neutrophils to Orchestrate Pulmonary Homeostasis

Neutrophils are the most abundant immune cells that constantly patrol and marginate into the vascular beds of multiple tissues to support immune homeostasis. The extent to which neutrophils undergo adaptation in response to diverse tissue microenvironments, and the resultant biological implications of such adaptation, remains unclear. Here, we performed intravital imaging, transcriptional, and functional analyses of neutrophils in different tissues. Our findings showed that the lung harbors a transcriptionally distinct neutrophil population with unique migratory behaviors. These resident-like neutrophils guarantee a rapid response upon infection and play an important role in maintaining the homeostasis of pulmonary vasculature. Notably, pulmonary neutrophils are imprinted by mechanical cues via the mechanosensitive ion channel Piezo1. Mice with conditional Piezo1 ablation lost lung-specific neutrophil signatures, and showed impaired lung capillary angiogenesis. Furthermore, these mice displayed increased susceptibility to airway infection. Collectively, these data identify mechanical sensing via Piezo1 as an important driver for tissue-specialized neutrophils that support pulmonary homeostasis.

immunology↗

bioRxiv2023

High-throughput confocal airy beam oblique light-sheet tomography of brain-wide imaging at single-cell resolution

Brain research is an area of research characterized by its cutting-edge nature, with brain mapping constituting a crucial aspect of this field. As sequencing tools have played a crucial role in gene sequencing, brain mapping largely depends on automated, high-throughput and high-resolution imaging techniques. Over the years, the demand for high-throughput imaging has scaled exponentially with the rapid development of microscopic brain mapping. In this paper, we introduce the novel concept of confocal Airy beam into oblique light-sheet tomography named CAB-OLST. We demonstrate that this technique enables the high throughput of brain-wide imaging of long-distance axon projection for the entire mouse brain at a resolution of 0.26 m x 0.26 m x 1.06 m in 58 hours. This technique represents an innovative contribution to the field of brain research by setting a new standard for high-throughput imaging techniques.

neuroscience↗

bioRxiv2023

Sex-biased regulatory changes in the placenta of native highlanders contribute to adaptive fetal development

Compared with lowlander migrants, native Tibetans have a higher reproductive success at high altitude though the underlying mechanism remains unclear. Here, we compared the transcriptome and histology of full-term placentas between native Tibetans and Han migrants. We found that the placental trophoblast shows the largest expression divergence between Tibetans and Han, and Tibetans show decreased immune response and endoplasmic reticulum stress. Remarkably, we detected a sex-biased expression divergence, where the male-infant placentas show a greater between-population difference than the female-infant placentas. The umbilical cord plays a key role in the sex-biased expression divergence, which is associated with the higher birth weight of the male newborns of Tibetans. We also identified adaptive histological changes in the male-infant placentas of Tibetans, including larger umbilical artery wall and umbilical artery intima and media, and fewer syncytial knots. These findings provide valuable insights into the sex-biased adaptation of human populations, with significant implications for medical and genetic studies of human reproduction.

evolutionary biology↗

bioRxiv2023

Induced pluripotent stem cell model revealed impaired neurovascular interaction in genetic small vessel disease CADASIL

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is the most common genetic small vessel disease caused by variants in the NOTCH3 gene. Patients with CADASIL experience recurrent strokes, developing into cognitive defect and vascular dementia. CADASIL is a late-onset vascular condition, but migraine and brain MRI lesions appear in CADASIL patients as early as their teens and twenties, suggesting an abnormal neurovascular interaction at the neurovascular unit (NVU) where microvessels meet the brain parenchyma. To understand the molecular mechanisms of CADASIL, we established induced pluripotent stem cell (iPSC) models from CADASIL patients and differentiated the iPSCs into the major NVU cell types including brain microvascular endothelial-like cells (BMECs), vascular mural cells (MCs), astrocytes and cortical projection neurons. We then built an in vitro NVU model by co-culturing different neurovascular cell types in Transwells and evaluated the blood brain barrier (BBB) function by measuring transendothelial electrical resistance (TEER). Results showed that, while the wild-type MCs, astrocytes and neurons could all independently and significantly enhance TEER values of the iPSC-BMECs, such capability of MCs from iPSCs of CADASIL patients was significantly impeded. Additionally, the barrier function of the BMECs from CADASIL iPSCs was significantly impaired, accompanied with disorganised tight junctions in iPSC-BMECs, which could not be effectively rescued by the wild-type MCs, astrocytes and neurons. Our findings provide new insight into early disease pathologies on the neurovascular interaction and BBB function at the molecular and cellular levels for CADASIL, which helps inform future therapeutic development.

cell biology↗

bioRxiv2023

NanoMOFs with Encapsulated Photosensitizer: Accumulation in Chlamydia trachomatis Inclusions and Antimicrobial Effects

Metal-organic framework nanoparticles (nanoMOFs) are a promising class of hybrid nanomaterials for biomedical applications. Some of them, including biodegradable porous iron carboxylates are proposed for encapsulation and delivery of antibiotics. Due to the high drug loading capacity and fast internalization kinetics nanoMOFs are more beneficial for the treatment of intracellular bacterial infections compared to free antibacterial drugs, which poorly accumulate inside the cells because of the inability to cross membrane barriers or have low intracellular retention. However, nanoparticle internalization does not ensure their accumulation in the cell compartment that shelters a pathogen. This study shows the availability of MIL-100(Fe) MOF nanoparticles to co-localize with Chlamydia trachomatis, an obligate intracellular bacterium, in the infected RAW264.7 macrophages. Furthermore, nanoMOFs loaded with photosensitizer methylene blue (MB) exhibit complete photodynamic inactivation of Chlamydia trachomatis growth. Simultaneous infection and treatment of RAW264.7 cells with empty nanoMOFs resulted in a 3-fold decrease in bacterial load that indicates an intrinsic anti-chlamydial effect of this iron-containing nanomaterial. Thus, our findings suggest the use of iron-based nanoMOFs as a promising drug delivery platform, which contributes to antibacterial effect, for the treatment of chlamydial infections.

biophysics↗

bioRxiv2023

NRF2 deficiency promotes ferroptosis of astrocytes mediated by oxidative stress in Alzheimer's disease

Oxidative stress is involved in the pathogenesis of Alzheimers disease (AD), which is linked to reactive oxygen species (ROS), lipid peroxidation, and neurotoxicity. Emerging evidence suggests a role of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a major source of antioxidant response elements in AD. The molecular mechanism of oxidative stress and ferroptosis in astrocytes in AD is not yet fully understood. Here, we aim to investigate the mechanism by which Nrf2 regulates the ferroptosis of astrocytes in AD. Postmortem frontal cortex tissues from patients with AD and nondemented controls and brain tissue from the 3xTg AD mouse model and wild-type mice (10 months old) were used. Immunofluorescence staining for Nrf2, the ROS marker NADPH oxidase 4 (NOX4), and GFAP was performed. We further induced Nrf2 deficiency in mouse astrocytes by using RNAi and assessed the changes in ROS, ferroptosis, lipid peroxidation, and mitochondrial dysfunction by using western blotting and immunofluorescence staining. We found decreased expression of Nrf2 and upregulated expression of NOX4 in the frontal cortex from patients with AD and in the cortex of 3xTg mice compared to control mice. We demonstrated that Nrf2 deficiency led to ferroptosis-dependent oxidative stress-induced ROS with downregulated heme oxygenase-1 and glutathione peroxidase 4 and upregulated cystine glutamate expression. Moreover, Nrf2 deficiency increased lipid peroxidation, DNA oxidation, and mitochondrial fragmentation in mouse astrocytes. In conclusion, these results suggest that Nrf2 promotes ferroptosis of astrocytes involving oxidative stress in AD.

neuroscience↗

bioRxiv2023

Gastrodin ameliorates synaptic impairment, reestablishes mitochondrial membrane potential and reduces oxidative stress in N2a/APP cells through the ERK1/2 and GSK-3beta pathways

Alzheimers disease (AD) is featured by abnormal {beta}-amyloid (A{beta}) deposition, neurofibrillary tangle formation, downstream mitochondrial dysfunction, oxidative stress, and synaptic loss. Gastrodin, a phenolic glycoside, has shown neuroprotective effect and used in the treatment of a range of brain diseases. Here we aim to assess the mechanisms and signaling pathways involved in the neuroprotective effect of gastrodin in murine neuroblastoma N2a cells expressing human Swedish mutant amyloid precursor protein (N2a/APP). The levels of pre- and postsynaptic proteins, amyloid precursor protein C-terminal fragments (APP-CTFs), levels of tau, glycogen synthase kinase-3 {beta} (GSK-3{beta}), extracellular regulated kinase (ERK), and c-Jun N-terminal Kinase (JNK) were assessed by Western blotting. Flow cytometry assays for mitochondrial membrane potential (JC1) and reactive oxidative stress, as well as immunofluorescence staining for lipid peroxidation (4{square}hydroxynonenal) and DNA oxidation (8{square}hydroxy{square}2{square}deoxyguanosine), were performed. We found that gastrodin treatment increased the levels of presynaptic SNAP25, synaptophysin, and postsynaptic PSD95, reduced phosphorylated tau protein Ser396, and APP-CTFs in N2a/APP cells. In addition, gastrodin reduced the levels of reactive oxygen species generation, lipid peroxidation, and DNA oxidation, reestablished mitochondrial membrane potential. Upregulated levels of phosphorylated-GSK-3{beta}, reduced levels of phosphorylated-ERK, and phosphorylated-JNK were involved the protective effect of gastrodin. In conclusion, we demonstrated a neuroprotective effect of gastrodin in N2a/APP cell line.

neuroscience↗

bioRxiv2023

Myricetin protected against Aβ oligomer-induced synaptic impairment, mitochondrial function and oxidative stress in SH-SY5Y cells via ERK1/2/GSK-3β pathways

Alzheimers disease is characterized by abnormal {beta}-amyloid (A{beta}) plaque accumulation, tau hyperphosphorylation, reactive oxidative stress, mitochondrial dysfunction and synaptic loss. Myricetin, a dietary flavonoid, has been shown to have neuroprotective effects in vitro and in vivo. Here, we aimed to elucidate the mechanism and pathways involved in myricetins protective effect on the toxicity induced by the A{beta}42 oligomer. Neuronal SH-SY5Y cells were pretreated with myricetin before incubation with A{beta}42 oligomer. The levels of pre- and postsynaptic proteins, mitochondrial division and fusion proteins, glycogen synthase kinase-3 {beta} (GSK-3{beta}) and extracellular regulated kinase (ERK) 1/2 were assessed by Western blotting. Flow cytometry assays for mitochondrial membrane potential (JC1) and reactive oxidative stress, as well immunofluorescence staining for lipid peroxidation (4-HNE) and DNA oxidation (8-OHdG), were performed. We found that myricetin prevented A{beta}42 oligomer-induced tau phosphorylation and the reduction in pre/postsynaptic proteins. In addition, myricetin reduced reactive oxygen species generation, lipid peroxidation, and DNA oxidation induced by the A{beta}42 oligomer. Moreover, myricetin prevented the A{beta}42 oligomer-induced reduction in mitochondrial fusion proteins (mitofusin-1, mitofusin-2), fission protein (dynamin-related protein 1) phosphorylation, and mitochondrial membrane potential via the associated GSK-3{beta} and ERK 1/2 signaling pathways. In conclusion, this study provides new insight into the neuroprotective mechanism of myricetin against A{beta}42 oligomer-induced toxicity.

neuroscience↗

bioRxiv2022

Regulation of adventitial interstitial fluid circulation by heartbeat and respiration

Converging studies showed interstitial fluid (ISF) adjacent to blood vessels flows along adventitia of vasculature into heart and lungs. We aim to reveal circulatory pathways and regulatory mechanism of such adventitial ISF flow in rat model. By MRI, real-time fluorescent imaging, micro-CT and histological analysis, ISF was found to flow in adventitial matrix surrounded by fascia and along systemic vessels into heart, then flow into lungs via pulmonary arteries and back to heart via pulmonary veins, which was neither perivascular tissues nor blood or lymphatic vessels. Under physiological conditions, speckle-like adventitial ISF flow rate was positively correlated with heart rate, increased when holding breath, became pulsative during heavy breathing. During cardiac or respiratory cycle, each dilation or contraction of heart or lungs can generate to-and-fro adventitial ISF flow along femoral veins. Discovered regulatory mechanisms of adventitial ISF flow along vasculature by heart and lungs will revolutionize understanding of cardiovascular system. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=159 SRC="FIGDIR/small/512678v3_ufig1.gif" ALT="Figure 1"> View larger version (68K): org.highwire.dtl.DTLVardef@1d29c16org.highwire.dtl.DTLVardef@583f5org.highwire.dtl.DTLVardef@1a551eorg.highwire.dtl.DTLVardef@ca4780_HPS_FORMAT_FIGEXP M_FIG Graphic abstract of adventitial interstitial fluid cycle by heartbeat and respiration.The heart and lungs can work together to regulate the ISF (green arrow) adjacent to blood vessels to flow centripetally in an adventitial pathway along the major arteries and veins of the systemic vasculature to the epicardium and myocardium, then flow into the lungs via the pulmonary arteries and back to the heart via the pulmonary veins, forming an adventitial ISF circulatory network. Under physiological conditions, the speckle-like adventitial ISF flow rate was positively correlated with heart rate, increased when holding breath, and became pulsative during heavy breathing. During respiratory cycle, each expansion of the lungs during inflation generates a centrifugal flow of adventitial ISF along the systemic veins, while each contraction of the lungs during deflation generates a centripetal adventitial ISF flow. During cardiac cycle, each dilation of atria or ventricles generates a centripetal flow of adventitial ISF along the systemic veins, while each contraction of atria or ventricles generates a centrifugal adventitial ISF flow. C_FIG

physiology↗

bioRxiv2022

Prefrontal neuronal dynamics in the absence of task execution

Prefrontal cortical activity represents stimuli in working memory tasks in a low-dimensional manifold that transforms over the course of a trial. Such transformations reflect specific cognitive operations, so that, for example, the rotation of stimulus representations is thought to reduce interference by distractor stimuli. Here we show that rotations occur in the low-dimensional activity space of prefrontal neurons in naive monkeys, while passively viewing familiar stimuli. Moreover, some aspects of these rotations remain remarkably unchanged after training to perform working memory tasks. Significant training effects are still present in population dynamics, which further distinguish correct and error trials during task execution. Our results reveal automatic functions of prefrontal neural circuits, allow transformations that may aid cognitive flexibility.

neuroscience↗

bioRxiv2022

Quercetin reduces APP expression, oxidative stress and mitochondrial dysfunction in the N2a/APPswe cells via ERK1/2 and AKT pathways

Abnormal amyloid-{beta} (A{beta}) abnormal accumulation and oxidative stress play important roles in Alzheimers disease (AD). Quercetin has been reported to possess antioxidant and anti-inflammatory properties, and thus of therapeutic interests for neurodegenerative disorders. In the present study, we aimed to characterize the mechanisms by which quercetin exerts neuroprotective effects in murine neuroblastoma N2a cells stably expressing human Swedishh mutant amyloid precursor protein (APP). Quercetin treatment exhibited low cytoxicity, attenuated APP expression and APP-induced oxidative neurotoxicity in N2a/APP cells. We found that quercetin effected via the down-regulation of phospho-extracellular signal{square}regulated protein kinase (p-ERK1/2) pathway and up-regulation of phospho-protein kinase B (p-AKT) pathway in N2a/APP cells. In addition, quercetin ameliorated the elevated levels of reactive oxygen species using DCFH-DA flow-cytometry in N2a/APP cells, lipid peroxidation using (4-HNE), and DNA oxidation (8-OHdG assays). Quercetin ameliorated the loss of mitochondrial membrane potential using JC-1 fluorescence assay in N2a/APP cells in a dose-dependent mannor. In conclusion, we domenstrated the neuroprotective effects of quercetin against the APP expression induced oxidative neurotoxicity, impairment of mitochondrial function and oxidative stress through inactivation of the ERK1/2 signaling pathway and activation of AKT signaling pathways.

neuroscience↗

bioRxiv2022

A Genome-scale Screen Reveals ANTXR1, Heparan Sulfate and Neu5Gc as Host Factors mediating Seneca Valley virus Entry into Porcine Cells

Seneca Valley virus (SVV) disease is a newly emerging infectious disease of pigs caused by SVV, which seriously endangers the pig industry. This study was set out to identify the essential host factors required for SVV entering porcine cells. Using a CRISPR/Cas9 library containing 93,859 sgRNAs that were designed to target approximately 22,707 porcine genes, we generated mutated porcine cell libraries, which were subjected to SVV challenge for enrichment of cells resistant to SVV infection. These resistant cells were subsequently analyzed to identify genes essential for SVV infection. We demonstrated that ANTXR1, a type I transmembrane protein encoded by ANTXR1, heparan sulfate (HS), glycosaminoglycans modified by acetylation and sulfation of HS2ST1, and Neu5Gc, a non-human sialic acid catalyzed by CMAH, were the essential host factors for SVV entry into porcine cells. These results will be helpful to elucidate the pathogenesis of SVV and the development of prevention and control measures.

pathology↗

bioRxiv2022

PRMT5 is a therapeutic target in choroidal neovascularization

Ocular neovascular diseases including neovascular age-related macular degeneration (nvAMD) are widespread causes of blindness. Patients non-responsiveness to currently used biologics that target vascular endothelial growth factor (VEGF) poses an unmet need for novel therapies. Here, we identify protein arginine methyltransferase 5 (PRMT5) as a novel therapeutic target for nvAMD. PRMT5 is a well-known epigenetic enzyme. We previously showed that PRMT5 methylates and activates a proangiogenic and proinflammatory transcription factor, the nuclear factor kappa B (NF-{kappa}B), which has a master role in tumor progression, notably in pancreatic ductal adenocarcinoma and colorectal cancer. We identified a potent and specific small molecule inhibitor of PRMT5, PR5-LL-CM01, that dampens the methylation and activation of NF-{kappa}B. Here for the first time, we assessed the antiangiogenic activity of PR5-LL-CM01 in ocular cells. Immunostaining of human nvAMD sections revealed that PRMT5 is highly expressed in the retinal pigment epithelium (RPE)/choroid where neovascularization occurs, while mouse eyes with laser induced choroidal neovascularization (L-CNV) showed PRMT5 is overexpressed in the retinal ganglion cell layer and in the RPE/choroid. Importantly, inhibition of PRMT5 by PR5-LL-CM01 or shRNA knockdown of PRMT5 in human retinal endothelial cells (HRECs) and induced pluripotent stem cell (iPSC)-derived choroidal endothelial cells (iCEC2) reduced NF-{kappa}B activity and the expression of its target genes, such as tumor necrosis factor (TNF-) and VEGF-A. In addition to inhibiting angiogenic properties of proliferation and tube formation, PR5-LL-CM01 blocked cell cycle progression at G1/S-phase in a dose-dependent manner in these cells. Thus, we provide the first evidence that inhibition of PRMT5 impedes angiogenesis in ocular endothelial cells, suggesting PRMT5 as a potential therapeutic target to ameliorate ocular neovascularization.

pharmacology and toxicology↗

bioRxiv2022

Dual-Resolving of Lipid Positional and Geometric Isomers of C=C Bonds via Bifunctional Photocycloaddition-Photoisomerization Reaction System and Mass Spectrometry

The biological functions of lipids largely depend on their chemical structures. The position and configuration of C=C bonds are two of the essential attributes that determine the structures of unsaturated lipids. However, simultaneous identification of both attributes remains challenging. Here, we developed a bifunctional visible-light-activated photocycloaddition-photoisomerization reaction system, which enabled the dual-resolving of the positional and geometric isomerism of C=C bonds in lipids when combined with liquid chromatographic mass spectrometry. The dual-pathway reaction mechanism was demonstrated by experiments and density functional theory calculations. Based on this bifunctional reaction system, a workflow of deep structural lipidomics was established, and allowed the revealing of unique patterns of cis-trans-isomers in bacteria, as well as the tracking of C=C positional isomers changes in mouse brain ischemia. This study not only offers a powerful tool for deep lipid structural biology, but also provides a new paradigm for developing the multifunctional visible-light-induced reaction.

biochemistry↗