Scutellaria barbata D. Don Polysaccharides Inhibit High Glucose-Induced Proliferation and Angiogenesis of Retinal Vascular Endothelial Cells

Underlying mechanisms of traditional Chinese medicine in the prevention and treatment of diabetic retinopathy: Evidences from molecular and clinical studies

As one of the most serious microvascular complications of diabetes mellitus (DM), diabetic retinopathy (DR) can cause visual impairment and even blindness. With the rapid increase in the prevalence of DM, the incidence of DR is also rising year by year. Preventing and effectively treating DR has become a major focus in the medical field. Traditional Chinese medicine (TCM) has a wealth of experience in treating DR and has achieved significant results with various herbs and TCM prescriptions. Traditional Chinese Medicine (TCM) provides a comprehensive therapeutic strategy for diabetic retinopathy (DR), encompassing anti-inflammatory and antioxidant actions, anti-neovascularization, neuroprotection, regulation of glucose metabolism, and inhibition of apoptosis. This review provides an overview of the current status of TCM treatment for DR in recent years, including experimental studies and clinical researches, to explore the clinical efficacy and the underlying modern mechanisms of herbs and TCM prescriptions. Besides, we also discussed the challenges TCM faces in treating DR, such as drug-drug interactions among TCM components and the lack of high-quality evidence-based medicine practice, which pose significant obstacles to TCM's application in DR.

Polysaccharides from Ostrea rivularis alleviate type II diabetes induced-retinopathy and VGEF165-induced angiogenesis via PI3K/AKT signaling pathway

The purpose of this study was to investigate the role of polysaccharides from Ostrea rivularis Gloud (ORPs) in the progression of diabetic retinopathy (DR) and its anti-angiogenic effect on endothelial cell. Transgenic db/db mice with DR model were used to evaluate the protective effect of ORPs on retinal damage. It was found that ORPs could down-regulated levels of random blood glucose and fasting insulin, and further ameliorate retinal structure abnormalities as well as vascular network structure. Moreover, ORPs could reduce the expression of VEGF in retinal tissue and lessen pathological angiogenesis, thus slowing the progression of DR. In vitro, the proliferation, migration and tube formation of VGEF165-induced EA.hy926 cells were inhibited with ORPs administration. Furthermore, the expression of related proteins in the PI3K/AKT pathway and angiogenesis related factors were improved after ORPs intervention. Overall, these findings suggested that ORPs could effectively control the development of DR, and inhibit VGEF165-induced EA.hy926 cells proliferation, migration and tube formation, which effects might work through blocking the activation of PI3K/AKT signaling pathway.

Research Progress on the Anticancer Activity of Plant Polysaccharides

Tumor is a serious threat to human health, with extremely high morbidity and mortality rates. However, tumor treatment is challenging, and the development of antitumor drugs has always been a significant research focus. Plant polysaccharides are known to possess various biological activities. They have many pharmacological properties such as immunomodulation, antitumor, antiviral, antioxidative, antithrombotic, and antiradiation effects, reduction of blood pressure and blood sugar levels, and protection from liver injury. Among these effects, the antitumor effect of plant polysaccharides has been widely studied. Plant polysaccharides can inhibit tumor proliferation and growth by inhibiting tumor cell invasion and metastasis, inducing cell apoptosis, affecting the cell cycle, and regulating the tumor microenvironment. They also have the characteristics of safety, high efficiency, and low toxicity, which can alleviate, to a certain extent, the adverse reactions caused by traditional tumor treatment methods such as surgery, radiotherapy, and chemotherapy. Therefore, this paper systematically summarizes the direct antitumor effects of plant polysaccharides, their regulatory effects on the tumor microenvironment, and intervening many common high-incidence tumors in other ways. It also provides data support for the administration of plant polysaccharides in modern tumor drug therapy, enabling the identification of new targets and development of new drugs for tumor therapy.

Cell Division Control Protein 42 Facilitates Diabetic Retinopathy Progression by Activating the MEK/ERK Pathway

Cell division control protein 42 (CDC42) modulates insulin secretion and angiogenesis to participate in the pathology of diabetic complications and retinal vascular-associated diseases. This study intended to explore the role of CDC42 in the progression of diabetic retinopathy, and the underlying mechanism. Human retinal microvascular endothelial cells (hRMECs) were cultured in 5.5 mM glucose (normal glucose) or 25 mM glucose (high glucose; HG) medium, respectively. CDC42 overexpression plasmid and small interference RNA (oe-CDC42 and si-CDC42) or corresponding negative controls (oe-NC and si-NC) were transfected into hRMECs under HG. Then, platelet-activating factor C-16 (C16-PAF) (MEK/ERK pathway activator) was added to si-CDC42 or si-NC transfected hRMECs under HG. Our study showed that HG increased CDC42 mRNA and protein, cell viability, invasive cell count, branch points, and tube length but reduced cell apoptosis in hRMECs. CDC42 upregulation enhanced cell viability, invasive cell count, branch points, tube length, p-MEK, and p-ERK, but attenuated cell apoptosis. Downregulation of CDC42 exhibited opposite trends. In addition, C16-PAF also increased cell viability, invasive cell count, branch points, and tube length, p-MEK, and p-ERK, but retarded cell apoptosis. Notably, C16-PAF diminished the effect of CDC42 downregulation on the above-mentioned functions in hRMECs under HG. Conclusively, CDC42 promotes HG-induced hRMEC viability and invasion, as well as angiogenesis, but inhibits apoptosis by activating the MEK/ERK pathway, which may be responsible for the progression of diabetic retinopathy.

The signaling pathways of traditional Chinese medicine in treating diabetic retinopathy

Diabetic retinopathy (DR) is one of the common diabetic microvascular complications that occurs in the eyes and is closely associated with vision loss in working adults. However, the clinical treatment of DR is limited or accompanied by a large number of complications. Therefore, the development of new drugs for the treatment of DR is urgently needed. Traditional Chinese medicine (TCM) is widely used to treat DR in China, and its multi-pathway and multi-level characteristics can effectively address the complex pathogenesis of DR. Growing evidence suggests that inflammation, angiogenesis, and oxidative stress are the core pathological mechanisms in the development of DR. This study innovatively considers the aforementioned processes as the fundamental unit and sheds light on the molecular mechanisms and potential of TCM against DR in terms of signaling pathways. The results showed that NF-κB, MAPK/NF-κB, TLR4/NF-κB, VEGF/VEGFR2, HIF-1α/VEGF, STAT3, and Nrf2/HO-1 are the key signaling pathways for the treatment of DR by TCMs, which involved curcumolide, erianin, quercetin, blueberry anthocyanins, puerarin, arjunolic acid, ethanol extract of Scutellaria barbata D. Don, Celosia argentea L. extract, ethanol extract of Dendrobium chrysotoxum Lindl., Shengpuhuang-tang, and LuoTong formula. The purpose of this review is to update and summarize the signaling pathways of TCM in the treatment of DR and provide ideas for the development of new drugs against DR in the future.

Progress in Traditional Chinese Medicine on Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR), a common and blinding diabetic microvascular complication, is a harmful metabolic effect caused by persistent hyperglycemia. Owing to the complex pathogenesis of DR, various clinical treatment methods cannot completely prevent its development and are accompanied by various complications. Therefore, there is an urgent need to identify new therapeutic drugs or complementary and alternative therapies. Traditional Chinese medicine (TCM) has the unique advantages of multi-level, multi-target, and minimal side effects. Accumulating evidence has proven that TCM may help delay or prevent the progression of DR. This paper reviews the effect and mechanism of representative TCMs (including extracts, identified compounds, and compound formulas) on DR in recent years and provides evidence for new drug development and clinical efficacy.

Transcription factor FOXP1 mediates vascular endothelial dysfunction in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is still the fastest growing cause of blindness in working aged adults, and its typical characteristics are endothelial cell dysfunction and pericytes loss. Transcription factor fork head box P1 (FOXP1) is a member of FOX family involved in diabetes progression and is expressed in endothelial cells. The purpose of this study was to investigate the role and mechanism of FOXP1 in DR.

METHODS

The vitreous of DR patients and non-DR patients were collected, and the expression of FOXP1 was detected by real-time polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Human umbilical vein endothelial cells (HUVECs) cultured in high glucose simulated DR environment, and the expressions of FOXP1, vascular endothelial growth factor (VEGF), and pigment epithelium derived factor (PEDF) were detected by RT-qPCR and western blot (WB) after transfection of small interfering RNA (siRNA) to knock out FOXP1. At the same time, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (MTT), 5-ethynyl-2'-deoxyuridine assay (EDU), flow cytometry, Transwell assay, and tube-forming experiment were performed to determine cell proliferation, migration, and tube-forming ability.

RESULTS

We found that FOXP1 was highly expressed in the vitreous of DR patients and HUVECs under high glucose condition. After FOXP1 was decreased, the activation of VEGF expression and inhibition of PEDF expression in HUVECs induced by high glucose were reversed; meanwhile, cell proliferation, migration, and tube formation decreased, and apoptosis was promoted.

CONCLUSION

Generally, FOXP1 is highly expressed in the vitreous of DR patients, and its silence prevented VEGF/PEDF signaling pathway stimulated by high glucose and also reduced the proliferation, migration, and tube formation of endothelial cell, thus improving vascular endothelial dysfunction caused by DR. The results indicate that FOXP1 may be a therapeutic target of DR.

Scutellaria barbata D.Don (SBD) extracts suppressed tumor growth, metastasis and angiogenesis in Prostate cancer via PI3K/Akt pathway

Background

Scutellaria barbata D.Don (SBD) is derived from the dried whole plant of Labiate which has been widely used to treat patients with multiple cancer. It was previously reported that the ethanol extract of SBD is able to promote apoptosis, and inhibit cell proliferation and angiogenesis in cancer.

Materials and methods

CCK8, Edu assays and colony formation assay were performed to assess the effect of SBD on PCa cell growth. Effect of SBD on apoptosis and cell cycle was detected by flow cytometry. Transwell and wounding healing assay were conducted to detect the invasion and migration activities of PCa cells. Western blot was employed to detect the protein expression. 2RRV1 mouse xenograft model was established to detect the effect of SBD on prostate cancer. Angiogenesis was analysed by coculturing PCa cell lines and HUVECs.

Results

The results showed that SBD induced a significant decrease in cell viability and clonogenic growth in a dose-dependent manner. SBD induced cell apoptosis and cell cycle G2/M phase arrest by inactivating PI3K/AKT signalling pathway. Treatment with SBD also significantly decreased the cell migration and invasion via phenotypic inversion of EMT that was characterized by the increased expression of E-cadherin and Vimentin, and decreased expression of N-cadherin, which could be partially attributed to inhibiting PI3K/AKT signalling pathway. Subsequently, using AKT inhibitor MK2206, we concluded that PI3K/AKT are also involved in cell apoptosis and metastasis of PCa cells stimulated by SBD. Apart from its direct effects on PCa cells, SBD also exhibited anti-angiogenic properties. SBD alone or conditioned media from SBD-treated PCa cells reduced HUVEC tube formation on Matrigel without affecting HUVEC viability. Furthermore, 22RV1 xenograft C57BL/6 mice treated with SBD in vivo showed a significant inhibitory in tumour size and tumour weight without toxicity. In addition, administration with medium- or high-dose of SBD significantly inhibited the cell proliferation and enhanced the damage to tumour tissues.

Conclusions

Collectively, our in vitro and in vivo findings suggest that SBD has the potential to develop into a safe and potent alternative therapy for PCa patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03587-0.

Extraction Optimization, Structural Characterization, and Anti-Hepatoma Activity of Acidic Polysaccharides From Scutellaria barbata D. Don

The Chinese medicinal herb Scutellaria barbata D. Don has antitumour effects and is used to treat liver cancer in the clinic. S. barbata polysaccharide (SBP), one of the main active components extracted from S. barbata D. Don, exhibits antitumour activity. However, there is still a lack of research on the extraction optimization, structural characterization, and anti-hepatoma activity of acidic polysaccharides from S. barbata D. Don. In this study, the optimal extraction conditions for SBP were determined by response surface methodology (RSM): the material-liquid ratio was 1:25, the extraction time was 2 h, and the extraction temperature was 90°C. Under these conditions, the average extraction efficiency was 3.85 ± 0.13%. Two water-soluble polysaccharides were isolated from S. barbata D. Don, namely, SBP-1A and SBP-2A, these homogeneous acidic polysaccharide components with average molecular weights of 1.15 × 10⁵ Da and 1.4 × 10⁵ Da, respectively, were obtained at high purity. The results showed that the monosaccharide constituents of the two components were fucose, galactosamine hydrochloride, rhamnose, arabinose, glucosamine hydrochloride, galactose, glucose, xylose, and mannose; the molar ratio of these constituents in SBP-1A was 0.6:0.3:0.6:30.6:3.3:38.4:16.1:8:1.4, and that in SBP-2A was 0.6:0.5:0.8:36.3:4.4:42.7:9.2:3.6:0.7. In addition, SBP-1A and SBP-2A contained uronic acid and β-glucan, and the residue on the polysaccharide was mainly pyranose. The in vitro results showed that the anti-hepatoma activity of SBP-2A was better than that of SBP-1A and SBP. In addition, SBP-2A significantly enhanced HepG2 cell death, as cell viability was decreased, and SBP-2A induced HepG2 cell apoptosis and blocked the G1 phase. This phenomenon was coupled with the upregulated expression of P53 and Bax/Bcl-2 ratio, as well as the downregulated expression of the cell cycle-regulating protein cyclinD1, CDK4, and Bcl-2 in this study. Further analysis showed that 50 mg/kg SBP-2A inhibited the tumour growth in H22 tumour-bearing mice, with an average inhibition rate of 40.33%. Taken together, SBP-2A, isolated and purified from S. barbata showed good antitumour activity in vivo and in vitro, and SBP-2A may be a candidate drug for further evaluation in cancer prevention. This study provides insight for further research on the molecular mechanism of the anti-hepatoma activity of S. barbata polysaccharide.