Infliximab relieves blood retinal barrier breakdown through the p38 MAPK pathway in a diabetic rat model

Alisol A, the Eye-Entering Ingredient of Alisma orientale, Relieves Macular Edema Through TNF-α as Revealed by UPLC-Triple-TOF/MS, Network Pharmacology, and Zebrafish Verification

Purpose

Alisma orientale (AO, Alisma orientale (Sam). Juzep) has been widely employed for the treatment of macular edema (ME) in traditional Chinese medicine due to its renowned water-relief properties. Nonetheless, the comprehensive investigation of AO in alleviating ME remained unexplored. This study aims to identify the active components of AO that target the eye and investigate its pharmacological effects and mechanisms on ME.

Methods

The study commenced with UPLC-Triple-TOF/MS analysis to identify the primary constituents of AO. Zebrafish eye tissues were then analyzed after a five-day administration of AO to detect absorbed components and metabolites. Subsequently, network pharmacology, molecular docking, and molecular dynamics simulations were employed to predict the mechanisms of ME treatment via biological target pathways. In vivo experiments were conducted to corroborate the pharmacological actions and mechanisms.

Results

A total of 7 compounds, consisting of 2 prototype ingredients and 5 metabolites (including isomers), were found to traverse the blood-eye barrier and localized within eye tissues. Network pharmacology results showed that AO played a role in the treatment of ME mainly by regulating the pathway network of PI3K-AKT and MAPK with TNF-α centered. Computational analyses suggested that 11-dehydro-16-oxo-24-deoxy-alisol A, a metabolite of alisol A, mitigates edema through TNF-α inhibition. Furthermore, zebrafish fundus confocal experiments and HE staining of eyes confirmed the attenuating effects of alisol A on fundus angiogenesis and ocular edema, representing the first report of AO's ME-inhibitory effects.

Conclusion

In this study, computational analyses with experimental validation were used to understand the biological activity and mechanism of alisol A in the treatment of ME. The findings shed light on the bioactive constituents and pharmacological actions of AO, offering valuable insights and a theoretical foundation for its clinical application in managing ME.

The mechanism of traditional medicine in alleviating ulcerative colitis: regulating intestinal barrier function

Ulcerative colitis (UC) is an idiopathic inflammatory disease mainly affects the large bowel and the rectum. The pathogenesis of this disease has not been fully elucidated, while the disruption of the intestinal barrier function triggered by various stimulating factors related to the host genetics, immunity, gut microbiota, and environment has been considered to be major mechanisms that affect the development of UC. Given the limited effective therapies, the treatment of this disease is not ideal and its incidence and prevalence are increasing. Therefore, developing new therapies with high efficiency and efficacy is important for treating UC. Many recent studies disclosed that numerous herbal decoctions and natural compounds derived from traditional herbal medicine showed promising therapeutic activities in animal models of colitis and have gained increasing attention from scientists in the study of UC. Some of these decoctions and compounds can effectively alleviate colonic inflammation and relieve clinical symptoms in animal models of colitis via regulating intestinal barrier function. While no study is available to review the underlying mechanisms of these potential therapies in regulating the integrity and function of the intestinal barrier. This review aims to summarize the effects of various herbal decoctions or bioactive compounds on the severity of colonic inflammation via various mechanisms, mainly including regulating the production of tight junction proteins, mucins, the composition of gut microbiota and microbial-associated metabolites, the infiltration of inflammatory cells and mediators, and the oxidative stress in the gut. On this basis, we discussed the related regulators and the affected signaling pathways of the mentioned traditional medicine in modulating the disruption or restoration of the intestinal barrier, such as NF-κB/MAPK, PI3K, and HIF-1α signaling pathways. In addition, the possible limitations of current studies and a prospect for future investigation and development of new UC therapies are provided based on our knowledge and current understanding. This review may improve our understanding of the current progression in studies of traditional medicine-derived therapies in protecting the intestinal barrier function and their roles in alleviating animal models of UC. It may be beneficial to the work of researchers in both basic and translational studies of UC.

BIBF1120 Protects against Diabetic Retinopathy through Neovascularization-Related Molecules and the MAPK Signaling Pathway

Diabetic retinopathy (DR) is one of the microvascular complications of diabetes mellitus and a major pathological feature of neovascular DR. These patients potentially experience vision impairment and blindness. Platelet-derived growth factor receptor β (PDGFRβ), fibroblast growth factor receptor 1 (FGFR1), and vascular endothelial growth factor receptor 2 (VEGFR2) are implicated in the DR pathogenesis. Nintedanib (BIBF1120) is an oral selective dual receptor tyrosine kinase (RTK) inhibitor of VEGFR2, FGFR1, and PDGFRβ. In this study, intravitreal injection of BIBF1120 blocked the phosphorylation of VEGFR2, FGFR1, PDGFRβ, and MAPK signaling pathway proteins in a streptozotocin (STZ)-induced diabetic retinopathy mouse model. In in vitro cell experiments, BIBF1120 did not change cellular activity under normal conditions, while it further suppressed the tube formation, migration, and proliferation of high glucose-induced human retinal microvascular endothelial cells (HRMECs). Additionally, BIBF1120 blocked the phosphorylation of p38, JNK, and ERK1/2 in high glucose-treating HRMECs. Our results indicate that the BIBF1120 treatment can be a novel potential drug to protect against DR.

Salusin-β Mediates High Glucose-Induced Inflammation and Apoptosis in Retinal Capillary Endothelial Cells via a ROS-Dependent Pathway in Diabetic Retinopathy

BACKGROUND

Diabetic retinopathy (DR) is characterized by retinal vascular endothelial cell death and vascular inflammation, which are microvascular complications of diabetes mellitus (DM). Salusin-β, a newly identified peptide, is closely associated with hypertension, atherosclerosis and diabetic cardiomyopathy. However, the exact role of salusin-β in high glucose (HG)-induced retinal capillary endothelial cell (REC) inflammation and apoptosis remains unclear.

PATIENTS AND METHODS

A total of 60 patients with type 2 diabetes and 20 healthy controls were included in this study. Based on fundus fluorescein angiography findings, the diabetic patients were divided into three subgroups: diabetes without retinopathy (DWR), non-proliferative DR (NPDR) and proliferative DR (PDR). Serum salusin-β levels were measured by enzyme-linked immunosorbent assay. Human RECs (HRECs) were cultured in normal glucose (NG) and HG medium with or without salusin-β. Salusin-β expression was analysed by Western blotting and immunofluorescence staining. Expression of the pro-inflammatory cytokines MCP-1, IL-1β, TNF-α, and VCAM-1 was analysed by Western blotting. Reactive oxygen species (ROS) production was measured with 2',7'-dichlorofluorescein diacetate (DCFH-DA). Cell apoptosis rates were determined by flow cytometry. The levels of p38, JNK, p-p38, and p-JNK and the apoptosis-related proteins cleaved caspase-3, Bax, and cl2 were analysed by Western blotting.

RESULTS

Serum salusin-β levels were higher in diabetic patients than in healthy controls (p = 0.0027), especially in patients with NPDR and PDR (both p<0.01). HG upregulated salusin-β expression in HRECs in a time-dependent manner. Salusin-β exacerbated inflammation and apoptosis, upregulated intracellular ROS production in HG-induced HRECs, and activated ROS-dependent JNK and p38 MAPK signalling, while knockdown of salusin-β suppressed these effects.

CONCLUSION

Our findings indicate that salusin-β can promote inflammation and apoptosis via ROS-dependent JNK and p38 MAPK signalling in HG-induced HRECs and could be a therapeutic target for DR.

The cGMP system in normal and degenerating mouse neuroretina: New proteins with cGMP interaction potential identified by a proteomics approach

The hereditary disease Retinitis pigmentosa results in severe vision loss due to photoreceptor degeneration by unclear mechanisms. In several disease models, the second messenger cGMP accumulates in the degenerating photoreceptors, where it may over‐activate specific cGMP‐interacting proteins, like cGMP‐dependent protein kinase. Moreover, interventions that counteract the activity of these proteins lead to reduced photoreceptor cell death. Yet there is little or no information whether other than such regular cGMP‐interactors are present in the retina, which we, therefore, investigated in wild‐type and retinal degeneration (rd1, rd10, and rd2) mouse models. An affinity chromatography based proteomics approach that utilized immobilized cGMP analogs was applied to enrich and select for regular and potentially new cGMP‐interacting proteins as identified by mass spectrometry. This approach revealed 12 regular and 10 potentially new retinal cGMP‐interacting proteins (e.g., EPAC2 and CaMKIIα). Several of the latter were found to be expressed in the photoreceptors and to have proximity to cGMP and may thus be of interest when defining prospective therapeutic targets or biomarkers for retinal degeneration.

Extracellular Vesicles and MicroRNA: Putative Role in Diagnosis and Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR) is a complex, progressive, and heterogenous retinal degenerative disease associated with diabetes duration. It is characterized by glial, neural, and microvascular dysfunction, being the blood-retinal barrier (BRB) breakdown a hallmark of the early stages. In advanced stages, there is formation of new blood vessels, which are fragile and prone to leaking. This disease, if left untreated, may result in severe vision loss and eventually legal blindness. Although there are some available treatment options for DR, most of them are targeted to the advanced stages of the disease, have some adverse effects, and many patients do not adequately respond to the treatment, which demands further research. Oxidative stress and low-grade inflammation are closely associated processes that play a critical role in the development of DR. Retinal cells communicate with each other or with another one, using cell junctions, adhesion contacts, and secreted soluble factors that can act in neighboring or long-distance cells. Another mechanism of cell communication is via secreted extracellular vesicles (EVs), through exchange of material. Here, we review the current knowledge on deregulation of cell-to-cell communication through EVs, discussing the changes in miRNA expression profiling in body fluids and their role in the development of DR. Thereafter, current and promising therapeutic agents for preventing the progression of DR will be discussed.