Puerarin regulates neovascular glaucoma through pigment epithelium‑derived growth factor‑induced NF‑κB signaling pathway

Pharmacological Activity, Pharmacokinetics, and Clinical Research Progress of Puerarin

As a kind of medicine and food homologous plant, kudzu root (Pueraria lobata (Willd.) Ohwi) is called an "official medicine" in Chinese folk medicine. Puerarin is the main active component extracted from kudzu root, and its structural formula is 8-β-D-grapes pyranose-4, 7-dihydroxy isoflavone, with a white needle crystal; it is slightly soluble in water, and its aqueous solution is colorless or light yellow. Puerarin is a natural antioxidant with high health value and has a series of biological activities such as antioxidation, anti-inflammation, anti-tumor effects, immunity improvement, and cardio-cerebrovascular and nerve cell protection. In particular, for the past few years, it has also been extensively used in clinical study. This review focuses on the antioxidant activity of puerarin, the therapy of diverse types of inflammatory diseases, various new drug delivery systems of puerarin, the "structure-activity relationship" of puerarin and its derivatives, and pharmacokinetic and clinical studies, which can provide a new perspective for the puerarin-related drug research and development, clinical application, and further development and utilization.

Mechanism of Secondary Glaucoma Development in HTLV-1 Uveitis

Human T-cell lymphotropic virus type 1 (HTLV-1) was the first retrovirus identified as the causative agent of human diseases, such as adult T-cell leukemia, HTLV-1-associated myelopathy, and HTLV-1 uveitis (HU). HU is one of the most frequent ocular inflammatory diseases in endemic areas, which has raised considerable public health concerns. Approximately 30% of HU patients develop secondary glaucoma, which is higher than the general uveitis incidence. We therefore investigated the mechanism underlying the high incidence of glaucoma secondary to HU in vitro. After contact with HTLV-1-producing T cells (MT-2), human trabecular meshwork cells (HTMCs) were infected. The infected cells increased in number, and nuclear factor (NF)-κB expression was activated. Contact between MT-2 cells and HTMCs resulted in significantly upregulated production of inflammatory cytokines, such as IL-6, and chemokines, such as CXCL10, CCL2, and CXCL-8. These findings indicate that the mechanism underlying secondary glaucoma in HU may involve proliferation of trabecular meshwork tissue after contact with HTLV-1-infected cells, resulting in decreased aqueous humor outflow. Upregulated production of inflammatory cytokines and chemokines simultaneously disrupts the normal trabecular meshwork function. This mechanism presumably leads to increased intraocular pressure, eventually resulting in secondary glaucoma.

Neuroprotective role of epigallocatechin-3-gallate in acute glaucoma via the nuclear factor-κB signalling pathway

Glaucoma is a disease involving impaired visual function accompanied by degeneration and necrosis of the optic nerve. Epigallocatechin-3-gallate (EGCG) exerts a neuroprotective effect against the degeneration of retinal ganglion cells. However, whether EGCG can relieve glaucoma and the possible mechanisms remain unclear. In order to determine the function of EGCG in glaucoma, an acute glaucoma rat model was established. Optic neuropathology was examined by haematoxylin-eosin staining and immunofluorescence staining for class III-β tubulin. The levels of inflammation-associated cytokines, such as interleukin (IL)-4, IL-6, TNF-α, IL-1β, IL-13 and IFN-γ were measured by flow cytometry. T cell proliferation was assessed by the carboxyfluorescein diacetate succinimidyl ester method. Finally, the functional role of EGCG in glaucoma was explored. The levels of the inflammation-associated proteins p-IκBα and p-p65 were measured by western blot analysis. The results showed that optic nerve injury occurred, and elevated levels of the inflammatory cytokines IL-4, IL-6, TNF-α, IL-1β, IL-13 and IFN-γ were observed in the rat model of acute glaucoma. In addition, an increased T lymphocyte proliferation rate and imbalance of Th1/Th2 cytokines were present in the models. Importantly, treatment with EGCG significantly alleviated optic nerve injury. At the molecular level, EGCG decreased the levels of inflammation-associated cytokines, decreased the proliferation rate of T lymphocyte cells, and repaired the imbalance of Th1/Th2 cytokines. Moreover, EGCG inhibited the increase in the phosphorylation of IκBα and p65 caused by modelling and thus suppressed the activation of the nuclear factor (NF)-κB signalling pathway. The findings of the present study indicate that EGCG could attenuate the symptoms of glaucoma and inhibit inflammatory responses by suppressing the NF-κB signalling pathway in a rat glaucoma model.

Targeting the NLRP3 Inflammasome in Glaucoma

Glaucoma is a group of optic neuropathies characterised by the degeneration of retinal ganglion cells, resulting in damage to the optic nerve head (ONH) and loss of vision in one or both eyes. Increased intraocular pressure (IOP) is one of the major aetiological risk factors in glaucoma, and is currently the only modifiable risk factor. However, 30–40% of glaucoma patients do not present with elevated IOP and still proceed to lose vision. The pathophysiology of glaucoma is therefore not completely understood, and there is a need for the development of IOP-independent neuroprotective therapies to preserve vision. Neuroinflammation has been shown to play a key role in glaucoma and, specifically, the NLRP3 inflammasome, a key driver of inflammation, has recently been implicated. The NLRP3 inflammasome is expressed in the eye and its activation is reported in pre-clinical studies of glaucoma. Activation of the NLRP3 inflammasome results in IL-1β processing. This pro inflammatory cytokine is elevated in the blood of glaucoma patients and is believed to drive neurotoxic inflammation, resulting in axon degeneration and the death of retinal ganglion cells (RGCs). This review discusses glaucoma as an inflammatory disease and evaluates targeting the NLRP3 inflammasome as a therapeutic strategy. A hypothetical mechanism for the action of the NLRP3 inflammasome in glaucoma is presented.

Altered spontaneous brain activity patterns in patients with neovascular glaucoma using amplitude of low-frequency fluctuations: A functional magnetic resonance imaging study

BACKGROUND

Neovascular glaucoma (NVG) can cause irreversible visual impairment and abnormal spontaneous changes in brain's visual system and other systems. There is little research on this aspect at present. However, amplitude of low-frequency fluctuations (ALFFs) can be used as an rs-fMRI analysis technique for testing changes in spontaneous brain activity patterns.

PURPOSE

The aim of this study was to probe the local characteristics of spontaneous brain activity in NVG patients and analyze their correlation with clinical behaviors.

METHODS

Resting-state functional magnetic resonance imaging (rs-fMRI) scans were obtained from eighteen patients with NVG (8 males, 10 females) and eighteen healthy controls (HCs; 8 males and 10 females) who were matched in age, gender, and education level. We evaluated spontaneous brain activity with the ALFF method. A receiver operating characteristic (ROC) curve was used to compare the average ALFF values for altered brain regions of NVG patients with those of HCs.

RESULTS

Compared with HCs, NVG patients had lower ALFF values in the right cuneus, right middle occipital gyrus, left cingulate gyrus, right precuneus, and left medial frontal gyrus (p < 0.001). Higher ALFF values were observed in the right superior frontal gyrus and left middle frontal gyrus (p < 0.001). Analysis of the ROC curves of the brain regions showed that the specificity and accuracy of ALFF values between NVG and HCs in the area under the curve were acceptable (p < 0.001).

CONCLUSION

The patients with NVG exhibited anomalous spontaneous activity in different brain regions; these finding should establish the foundation for a more comprehensive understanding of the pathological mechanisms of NVG. Furthermore, these abnormal variations in specific brain regions can be considered possible clinical indices of NVG.

Puerarin promotes DUSP1 expression by regulating miR‑133a‑3p in breast cancer

Previous studies demonstrated that puerarin represents a potential therapeutic drug for breast cancer treatment, due to its ability to inhibit the migration of MCF-7 and MDA-MB-231 cell lines. In order to investigate the mechanism of puerarin in breast cancer cells, the aim of the present study was to examine whether puerarin regulated the dual specificity phosphatase 1 (DUSP1) expression level by promoting the microRNA-133a-3p (miR-133a-3p) expression level in breast cancer. Cell viability and apoptosis were assessed in HCC38 cells by Cell Counting Kit-8 assays and a flow cytometry assay, respectively. In total, four treatment groups were considered: Puerarin treatment, miR-133a-3p mimics transfection, puerarin + miR-133a-3p mimics and negative control. miR-133a-3p expression and DUSP1 mRNA expression levels were analyzed by reverse transcription-quantitative polymerase chain reaction, and western blotting was used to detect the protein expression level. Furthermore, a luciferase reporter gene assay was used to test whether DUSP1 mRNA was a direct target of miR-133a-3p. The present results suggested that treatment with puerarin or miR-133a-3p mimics transfection affected the miR-133a-3p expression level and the activity of the DUSP1/p38 pathway, leading to inhibition of HCC38 cell viability and an increase in apoptosis. miR-133a-3p overexpression enhanced the drug action of peurarin. In conclusion, puerarin may increase DUSP1 expression by promoting the miR-133a-3p expression level in HCC38 breast cancer cells. Therefore, miR-133a-3p may represent a novel molecular marker for diagnosis and treatment of breast cancer, and puerarin may represent a promising clinical drug for treatment of patients with breast cancer.