PGF2α facilitates pathological retinal angiogenesis by modulating endothelial FOS-driven ELR+ CXC chemokine expression

Spatiotemporal dynamic changes of meningeal microenvironment influence meningeal lymphatic function following subarachnoid hemorrhage: from inflammatory response to tissue remodeling

BACKGROUND

Meningeal lymphatic vessels (mLVs) play a critical role in clearing erythrocytes from the subarachnoid space and immune cells from the brain parenchyma following subarachnoid hemorrhage (SAH). However, the drainage function of mLVs is impaired during the acute stage after SAH and gradually recovers in the subacute phase. We aimed to investigate the meningeal transcriptional response post-SAH and elucidate the dynamic influence of meningeal microenvironment on meningeal lymphatic function.

METHODS

We employed bioinformatics analysis of single-cell RNA sequencing and spatial transcriptomics to characterize the spatiotemporal dynamic changes in the early meningeal microenvironment post-SAH. In a mouse model of SAH, the early dynamic changes of the meningeal immune cells and the potential growth factor that promoted the early repair of the mLVs were further investigated and validated.

RESULTS

During the acute phase, myeloid cells early infiltrated the meninges and triggered inflammatory responses. In the subacute phase, the fibroblast population expanded significantly, contributing to tissue remodeling. The interplay between immune cells and fibroblasts regulated cell migration and phenotypic transition, potentially affecting the function of mLVs. Notably, placental growth factor (PGF) emerged as the most prominent ligand within the VEGF signaling pathway received by meningeal lymphatic endothelial cells (mLECs) post-SAH. This signaling event was associated with the early recovery of mLVs after acute immune responses.

CONCLUSIONS

Our study revealed a spatiotemporal transformation of the meningeal microenvironment from an "inflammatory response" phase to a "tissue remodeling" phase following SAH. Monocyte-derived macrophages and self-recruiting neutrophils contributed to impairment of mLVs in the acute stage, while PGF might serve as a key factor promoting early meningeal lymphatic function repair following the inflammatory response. These findings provided novel insights into the cellular dynamics underlying mLVs dysfunction and recovery post-SAH.

Hypoglycemia promotes inner blood-retinal barrier breakdown and retinal vascular leakage in diabetic mice

The blood-retinal barrier (BRB) serves as a physiological boundary regulating the passage of nutrients, waste, ions, proteins, and water to and from the retina. In patients with diabetic retinopathy, breakdown of the inner BRB (iBRB) results in damage to the neurovascular unit and is a principal cause of vision loss in the diabetic population. Here, we demonstrate that hypoglycemia, a common consequence of tight glycemic control and high glycemic variability, results in accumulation of the transcription factors hypoxia-inducible factor-1α (HIF-1α) and HIF-2α and the expression of dozens of HIF-dependent vasoactive mediators in the mouse retina. In diabetic mice, this modest increase in HIF-dependent hyperpermeability factors was sufficient to promote vesicular transcytosis, breakdown of the iBRB, and retinal vascular permeability. Genetic inhibition of either HIF-1α or HIF-2α resulted in an incomplete inhibition of the broad increase in HIF-regulated vasoactive gene expression in response to hypoglycemia. We therefore evaluated a pharmacologic dual HIF-1 and HIF-2 inhibitor, 32-134D, as a therapeutic approach to prevent hypoglycemia-induced HIF-dependent vasoactive gene expression. 32-134D effectively inhibited HIF-1α accumulation and HIF-regulated gene expression in human retinal tissue. In diabetic mice, intravitreal administration of 32-134D prevented the increase in expression of HIF-regulated vasoactive genes after transient episodes of hypoglycemia, blocking both breakdown of the iBRB and the promotion of retinal vascular hyperpermeability. Collectively, these observations help explain why patients with diabetes initiating tight glycemic control have worsening of their diabetic retinopathy and provide the foundation for clinical studies assessing HIF inhibition with 32-134D for its prevention.

Identification and Exploration of Immunity-Related Genes and Natural Products for Alzheimer's Disease Based on Bioinformatics, Molecular Docking, and Molecular Dynamics

BACKGROUND

Recent research highlights the immune system's role in AD pathogenesis and promising prospects of natural compounds in treatment. This study explores immunity-related biomarkers and potential natural products using bioinformatics, machine learning, molecular docking, and kinetic simulation.

METHODS

Differentially expressed genes (DEGs) in AD were analyzed using GSE5281 and GSE132903 datasets. Important AD module genes were identified using a weighted co-expression algorithm (WGCNA), and immune-related genes (IRGs) were obtained from the ImmPortPortal database. Intersecting these genes yielded important IRGs. Then, the least absolute shrinkage and selection operator (LASSO) and other methods screened common immune-related AD markers. Biological pathways were explored through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). The accuracy of these markers was assessed by subject operator signature (ROC) curves and validated in the GSE122063 dataset. The datasets was then subjected to immunoinfiltration analysis. Multiple compound databases were used to analyze core Chinese medicines and components. Molecular docking and kinetic simulation verification were used for further verification.

RESULTS

A total of 1360 differential genes and 5 biomarkers (PGF, GFAP, GPI, SST, NFKBIA) were identified, showing excellent diagnostic efficiency. GSEA revealed markers associated with Oxidative phosphorylation, Nicotine addiction, and Hippo signaling pathway. Immune infiltration analysis showed dysregulation in multiple immune cell types in AD brains, with significant interactions between markers and 5 immune cell types. A total of 27 possible herbs and 7 core compounds were eventually identified. The binding environment of GPI-luteolin and GPI-stigasterol was relatively stable and showed good affinity.

CONCLUSIONS

PGF, GFAP, SST, GPI, and NFKBIA were identified for early AD diagnosis, associated with immune cells and pathways in AD brains. 7 promising natural compounds, including luteolin and stigmasterol, were screened for targeting these biomarkers.

The lactylation modification of proteins plays a critical role in tumor progression

Lactylation modifications have been shown to be a novel type of protein post-translational modifications (PTMs), providing a new perspective for understanding the interaction between cellular metabolic reprogramming and epigenetic regulation. Studies have shown that lactylation plays an important role in the occurrence, development, angiogenesis, invasion and metastasis of tumors. It can not only regulate the phenotypic expression and functional polarization of immune cells, but also participate in the formation of tumor drug resistance through a variety of molecular mechanisms. In this review, we review the latest research progress of lactylation modification in tumors, focusing on its mechanism of action in angiogenesis, immune cell regulation in tumor microenvironment (TME), and tumor drug resistance, aiming to provide a theoretical basis and research ideas for the discovery of new therapeutic targets and methods. Through the in-depth analysis of lactylation modification, it is expected to open up a new research direction for tumor treatment and provide potential strategies for overcoming tumor drug resistance and improving clinical efficacy.

Prostanoid signaling in retinal cells elicits inflammatory responses relevant to early-stage diabetic retinopathy

Inflammation is a critical driver of the early stages of diabetic retinopathy (DR) and offers an opportunity for therapeutic intervention before irreversible damage and vision loss associated with later stages of DR ensue. Nonsteroidal anti-inflammatory drugs (NSAIDs) have shown mixed efficacy in slowing early DR progression, notably including severe adverse side effects likely due to their nonselective inhibition of all downstream signaling intermediates. In this study, we investigated the role of prostanoids, the downstream signaling lipids whose production is inhibited by NSAIDs, in promoting inflammation relevant to early-stage DR in two human retinal cell types: Müller glia and retinal microvascular endothelial cells. When cultured in multiple conditions modeling distinct aspects of systemic diabetes, Müller glia significantly increased production of prostaglandin E2 (PGE2), whereas retinal endothelial cells significantly increased production of prostaglandin F2α (PGF2α). Müller glia stimulated with PGE2 or PGF2α increased proinflammatory cytokine levels dose-dependently. These effects were blocked by selective antagonists to the EP2 receptor of PGE2 or the FP receptor of PGF2α, respectively. In contrast, only PGF2α stimulated adhesion molecule expression in retinal endothelial cells and leukocyte adhesion to cultured endothelial monolayers, effects that were fully prevented by FP receptor antagonist treatment. Together these results identify PGE2-EP2 and PGF2α-FP signaling as novel, selective targets for future studies and therapeutic development to mitigate or prevent retinal inflammation characteristic of early-stage DR.

Protein O-GlcNAcylation coupled to Hippo signaling drives vascular dysfunction in diabetic retinopathy

Metabolic disorder significantly contributes to diabetic vascular complications, including diabetic retinopathy, the leading cause of blindness in the working-age population. However, the molecular mechanisms by which disturbed metabolic homeostasis causes vascular dysfunction in diabetic retinopathy remain unclear. O-GlcNAcylation modification acts as a nutrient sensor particularly sensitive to ambient glucose. Here, we observe pronounced O-GlcNAc elevation in retina endothelial cells of diabetic retinopathy patients and mouse models. Endothelial-specific depletion or pharmacological inhibition of O-GlcNAc transferase effectively mitigates vascular dysfunction. Mechanistically, we find that Yes-associated protein (YAP) and Transcriptional co-activator with PDZ-binding motif (TAZ), key effectors of the Hippo pathway, are O-GlcNAcylated in diabetic retinopathy. We identify threonine 383 as an O-GlcNAc site on YAP, which inhibits its phosphorylation at serine 397, leading to its stabilization and activation, thereby promoting vascular dysfunction by inducing a pro-angiogenic and glucose metabolic transcriptional program. This work emphasizes the critical role of the O-GlcNAc-Hippo axis in the pathogenesis of diabetic retinopathy and suggests its potential as a therapeutic target.

Bruton's tyrosine kinase inhibition suppresses pathological retinal angiogenesis

BACKGROUND AND PURPOSE

Pathological retinal angiogenesis is a typical manifestation of vision-threatening ocular diseases. Many patients exhibit poor response or resistance to anti-vascular endothelial growth factor (VEGF) agents. Bruton's tyrosine kinase (BTK) controls the proliferation and function of immune cells. Therefore, we examined the anti-inflammatory and anti-angiogenic effects of BTK inhibition on retinal angiogenesis.

EXPERIMENTAL APPROACH

Retinal neovascularisation and vascular leakage in oxygen-induced retinopathy in C57/BL6J mice were assessed by whole-mount retinal immunofluorescence. PLX5622 was used to deplete microglia and Rag1-knockout mice were used to test the contribution of lymphocytes to the effects of BTK inhibition. The cytokines, activation markers, inflammatory and immune-regulatory activities of retinal microglia/macrophages were detected using qRT-PCR and immunofluorescence. NLRP3 was detected by western blotting, and the effects of BTK inhibition on the co-culture of microglia and human retinal microvascular endothelial cells (HRMECs) were examined.

KEY RESULTS

BTK inhibition suppressed pathological angiogenesis and vascular leakage, and significantly reduced retinal inflammation, which involved microglia/macrophages but not lymphocytes. BTK inhibition increased anti-inflammatory factors and reduced pro-inflammatory cytokines that resulted from NLRP3 inflammasome activation. BTK inhibition suppressed the inflammatory activity of microglia/macrophages, and acted synergistically with anti-VEGF without retinal toxicity. Moreover, the supernatant of microglia incubated with BTK-inhibitor reduced the proliferation, tube formation and sprouting of HRMECs.

CONCLUSION AND IMPLICATIONS

BTK inhibition suppressed retinal neovascularisation and vascular leakage by modulating the inflammatory activity of microglia and macrophages. Our study suggests BTK inhibition as a novel and promising approach for alleviating pathological retinal angiogenesis.

Prostanoid signaling in retinal vascular diseases

The vasculature of the retina is exposed to systemic and local factors that have the capacity to induce several retinal vascular diseases, each of which may lead to vision loss. Prostaglandin signaling has arisen as a potential therapeutic target for several of these diseases due to the diverse manners in which these lipid mediators may affect retinal blood vessel function. Previous reports and clinical practices have investigated cyclooxygenase (COX) inhibition by nonsteroidal anti-inflammatory drugs (NSAIDs) to address retinal diseases with varying degrees of success; however, targeting individual prostanoids or their distinct receptors affords more signaling specificity and poses strong potential for therapeutic development. This review offers a comprehensive view of prostanoid signaling involved in five key retinal vascular diseases: retinopathy of prematurity, diabetic retinopathy, age-related macular degeneration, retinal occlusive diseases, and uveitis. Mechanistic and clinical studies of these lipid mediators provide an outlook for therapeutic development with the potential to reduce vision loss in each of these conditions.

Research progress on interferon and cellular senescence

Since the 12 major signs of aging were revealed in 2023, people's interpretation of aging will go further, which is of great significance for understanding the occurrence, development, and intervention in the aging process. As one of the 12 major signs of aging, cellular senescence refers to the process in which the proliferation and differentiation ability of cells decrease under stress stimulation or over time, often manifested as changes in cell morphology, cell cycle arrest, and decreased metabolic function. Interferon (IFN), as a secreted ligand for specific cell surface receptors, can trigger the transcription of interferon-stimulated genes (ISGs) and play an important role in cellular senescence. In addition, IFN serves as an important component of SASP, and the activation of the IFN signaling pathway has been shown to contribute to cell apoptosis and senescence. It is expected to delay cellular senescence by linking IFN with cellular senescence and studying the effects of IFN on cellular senescence and its mechanism. This article provides a review of the research on the relationship between IFN and cellular senescence by consulting relevant literature.

Integrating Mendelian randomization and single-cell RNA sequencing to identify therapeutic targets of baicalin for type 2 diabetes mellitus

Background

Alternative and complementary therapies play an imperative role in the clinical management of Type 2 diabetes mellitus (T2DM), and exploring and utilizing natural products from a genetic perspective may yield novel insights into the mechanisms and interventions of the disorder.

Methods

To identify the therapeutic target of baicalin for T2DM, we conducted a Mendelian randomization study. Druggable targets of baicalin were obtained by integrating multiple databases, and target-associated cis-expression quantitative trait loci (cis-eQTL) originated from the eQTLGen consortium. Summary statistics for T2DM were derived from two independent genome-wide association studies available through the DIAGRAM Consortium (74,124 cases vs. 824,006 controls) and the FinnGen R9 repository (9,978 cases vs. 12,348 controls). Network construction and enrichment analysis were applied to the therapeutic targets of baicalin. Colocalization analysis was utilized to assess the potential for the therapeutic targets and T2DM to share causative genetic variations. Molecular docking was performed to validate the potency of baicalin. Single-cell RNA sequencing was employed to seek evidence of therapeutic targets' involvement in islet function.

Results

Eight baicalin-related targets proved to be significant in the discovery and validation cohorts. Genetic evidence indicated the expression of ANPEP, BECN1, HNF1A, and ST6GAL1 increased the risk of T2DM, and the expression of PGF, RXRA, SREBF1, and USP7 decreased the risk of T2DM. In particular, SREBF1 has significant interaction properties with other therapeutic targets and is supported by strong colocalization. Baicalin had favorable combination activity with eight therapeutic targets. The expression patterns of the therapeutic targets were characterized in cellular clusters of pancreatic tissues that exhibited a pseudo-temporal dependence on islet cell formation and development.

Conclusion

This study identified eight potential targets of baicalin for treating T2DM from a genetic perspective, contributing an innovative analytical framework for the development of natural products. We have offered fresh insights into the connections between therapeutic targets and islet cells. Further, fundamental experiments and clinical research are warranted to delve deeper into the molecular mechanisms of T2DM.

A feedback loop driven by H3K9 lactylation and HDAC2 in endothelial cells regulates VEGF-induced angiogenesis

BACKGROUND

Vascular endothelial growth factor (VEGF) is one of the most powerful proangiogenic factors and plays an important role in multiple diseases. Increased glycolytic rates and lactate accumulation are associated with pathological angiogenesis.

RESULTS

Here, we show that a feedback loop between H3K9 lactylation (H3K9la) and histone deacetylase 2 (HDAC2) in endothelial cells drives VEGF-induced angiogenesis. We find that the H3K9la levels are upregulated in endothelial cells in response to VEGF stimulation. Pharmacological inhibition of glycolysis decreases H3K9 lactylation and attenuates neovascularization. CUT& Tag analysis reveals that H3K9la is enriched at the promoters of a set of angiogenic genes and promotes their transcription. Interestingly, we find that hyperlactylation of H3K9 inhibits expression of the lactylation eraser HDAC2, whereas overexpression of HDAC2 decreases H3K9 lactylation and suppresses angiogenesis.

CONCLUSIONS

Collectively, our study illustrates that H3K9la is important for VEGF-induced angiogenesis, and interruption of the H3K9la/HDAC2 feedback loop may represent a novel therapeutic method for treating pathological neovascularization.

Expression of CXCL8 and its relationship with prognosis in patients with non-small cell lung cancer

To determine the expression of chemokine 8 (CXCL8) in non-small cell lung cancer (NSCLC) patients and analyze its correlation with tumor characteristics and patient prognosis. We conducted a retrospective analysis of 149 NSCLC patients treated between January 2016 and April 2018, measuring serum CXCL8 expression upon admission or prior to treatment. The clinical characteristics, including lymph node metastasis and staging, based on CXCL8 expression levels, were analyzed. Receiver Operating Characteristic (ROC) curves was drawn to assess its predictive value for lymph node metastasis and staging in NSCLC patients. Furthermore, the Kaplan-Meier curve was plotted to assess the impact of CXCL8 on 5-year survival in NSCLC Patients. NSCLC patients exhibited significantly higher serum CXCL8 levels than those with benign tumors (P<0.001), with the high CXCL8 expression group showing a higher incidence of lymph node metastasis or stage III NSCLC (P<0.01). CXCL8 was identified as an independent predictor of lymph node metastasis (AUC=0.730) and higher TNM stage (AUC=0.708), as well as a validated biomarker for predicting five-year survival in NSCLC patients. This study highlights the strong association between CXCL8 expression in NSCLC and patient prognosis, particularly regarding lymph node metastasis and clinical staging, suggesting the need for further research to explore CXCL8's specific role in the tumor microenvironment and its impact on different NSCLC subtypes.

Kinase PIM1 governs ferroptosis to reduce retinal microvascular endothelial cell dysfunction triggered by high glucose

Previous studies have implicated targeting Pim-1 proto-oncogene, serine/threonine kinase (PIM1) as a preventive measure against high glucose-induced cellular stress and apoptosis. This study aimed to reveal the potential role and regulatory mechanism of PIM1 in diabetic retinopathy. Human retinal microvascular endothelial cells (hRMECs) underwent high glucose induction, and fluctuations in PIM1 levels were assessed. By overexpressing PIM1, its effects on the levels of inflammatory factors, oxidative stress indicators, migration and tube formation abilities, tight junction protein expression levels, and ferroptosis in hRMECs were identified. Afterwards, hRMECs were treated with the ferroptosis-inducing agent erastin, and the effect of erastin on the above PIM1 regulatory functions was focused on. PIM1 was downregulated upon high glucose, and its overexpression inhibited the inflammatory response, oxidative stress, cell migration, and tube formation potential in hRMECs, whereas elevated tight junction protein levels. Furthermore, PIM1 overexpression reduced intracellular iron ion levels, lipid peroxidation, and levels of proteins actively involved in ferroptosis. Erastin treatment reversed the impacts of PIM1 on hRMECs, suggesting the mediation of ferroptosis in PIM1 regulation. The current study has yielded critical insights into the role of PIM1 in ameliorating high glucose-induced hRMEC dysfunction through the inhibition of ferroptosis.

Prostaglandin F2α Affects the Cycle of Clock Gene Expression and Mouse Behavior

Prostaglandins are bioactive compounds, and the activation of their receptors affects the expression of clock genes. However, the prostaglandin F receptor (Ptgfr) has no known relationship with biological rhythms. Here, we first measured the locomotor period lengths of Ptgfr-KO (B6.129-Ptgfrtm1Sna) mice and found that they were longer under constant dark conditions (DD) than those of wild-type (C57BL/6J) mice. We then investigated the clock gene patterns within the suprachiasmatic nucleus in Ptgfr-KO mice under DD and observed a decrease in the expression of the clock gene cryptochrome 1 (Cry1), which is related to the circadian cycle. Moreover, the expression of Cry1, Cry2, and Period2 (Per2) mRNA were significantly altered in the mouse liver in Ptgfr-KO mice under DD. In the wild-type mouse, the plasma prostaglandin F2α (PGF2α) levels showed a circadian rhythm under a 12 h cycle of light-dark conditions. In addition, in vitro experiments showed that the addition of PTGFR agonists altered the amplitude of Per2::luc activity, and this alteration differed with the timing of the agonist addition. These results lead us to hypothesize that the plasma rhythm of PGF2α is important for driving clock genes, thus suggesting the involvement of PGF2α- and Ptgfr-targeting drugs in the biological clock cycle.

Inflammatory cytokines as mediators of retinal endothelial barrier dysfunction in non-infectious uveitis

Characterised by intraocular inflammation, non-infectious uveitis includes a large group of autoimmune and autoinflammatory diseases that either involve the eye alone or have both ocular and systemic manifestations. When non-infectious uveitis involves the posterior segment of the eye, specifically the retina, there is substantial risk of vision loss, often linked to breakdown of the inner blood-retinal barrier. This barrier is formed by non-fenestrated retinal vascular endothelial cells, reinforced by supporting cells that include pericytes, Müller cells and astrocytes. Across the published literature, a group of inflammatory cytokines stand out as prominent mediators of intraocular inflammation, with effects on the retinal endothelium that may contribute to breakdown of the inner blood-retinal barrier, namely tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, IL-17 and chemokine C-C motif ligand (CCL)2. This article reviews the function of each cytokine and discusses the evidence for their involvement in retinal endothelial barrier dysfunction in non-infectious uveitis, including basic laboratory investigations, studies of ocular fluids collected from patients with non-infectious uveitis, and results of clinical treatment trials. The review also outlines gaps in knowledge in this area. Understanding the disease processes at a molecular level can suggest treatment alternatives that are directed against appropriate biological targets to protect the posterior segment of eye and preserve vision in non-infectious uveitis.