Investigation of expression and influence of CTGF and HO-1 in rats with diabetic retinopathy

Sorghum flour BRS 305 hybrid has the potential to modulate the intestinal microbiota of rats fed with a high-fat high-fructose diet

AIM

The present study aimed to investigate the effect of dry heated whole sorghum BRS 305 hybrid flour on the gut microbiota modulation and gut health of rats fed with a high-fat high-fructose diet (HFHF).

METHODS

In phase I (8 weeks), 45-50 days, male Wistar rats, were separated into the AIN93-M group (n = 10; fed with normal diet) and HFHF group (n = 20; fed with diet rich in saturated and simple carbohydrate). In phase II (10 weeks), we maintained the AIN-93-M group, and the HFHF group was divided into the HFHF group (n = 10) and HFHF plus sorghum flour group (n = 10).

RESULTS

The consumption of sorghum flour increased the circular muscle layer and propionic acid when compared to the HFHF group. The sequencing of the 16S rRNA gene of the cecal microbiota presented no changes in the α-diversity and β-diversity between. However, the sorghum group exhibited higher relative abundance of Firmicutes and higher Firmicutes/Bacteroidetes ratio compared to the other experimental groups, and lower abundance of Bacteroidetes, compared to the HFHF group. Despite, sorghum increased the abundance of the genera Roseburia and Lachnospiraceae_NK4A136_group compared to the HFHF group. No differences were observed in total goblet cell number, crypt thickness and height, circular muscle layer, secretory IgA, and butyric acid between all groups.

CONCLUSIONS

The consumption of sorghum flour can modulate the gut microbiota composition, abundance of SCFA-producing bacteria, and intestinal morphology even with consumption of an HFHF diet.

Transcriptional Network Analysis Reveals the Role of miR-223-5p During Diabetic Corneal Epithelial Regeneration

Diabetes mellitus (DM) is a complex metabolic disorder. Long-term hyperglycemia may induce diabetic keratopathy (DK), which is mainly characterized by delayed corneal epithelial regeneration. MicroRNAs (miRNAs) have been reported to play regulatory roles during tissue regeneration. However, the molecular mechanism by which miRNAs influence epithelial regeneration in DK is largely unknown. In this study, we performed miRNA and mRNA sequencing of regenerative corneal epithelium tissue from streptozotocin-induced type 1 diabetic (T1DM) and wild-type mice to screen for differentially expressed miRNAs and mRNAs. Based on regulatory network analysis, miR-223-5p was selected for subsequent experiments and Hpgds was then identified as a direct target gene. MiR-223-5p downregulation significantly promoted diabetic corneal epithelial wound healing and nerve regeneration. However, the beneficial effects of miR-223-5p inhibition were abolished by an Hpgds inhibitor. Furthermore, mechanistic studies demonstrated that miR-223-5p suppression ameliorated inflammation and enhanced cell proliferation signaling in DK. Taken together, our findings revealed that the regulatory role of miR-223-5p in diabetic corneal epithelial and nerve regeneration by mediating inflammatory processes and cell proliferation signaling. And silencing miR-223-5p may contribute to the development of potential therapeutic strategies for DK.

Dihydromyricetin Alleviates High Glucose-Induced Oxidative Stress and Apoptosis in Human Retinal Pigment Epithelial Cells by Downregulating miR-34a Expression

BACKGROUND

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes mellitus, which leads to neuronal and vascular dysfunction in the retina with a final outcome of complete loss of vision. The aim of the present study was to investigate the effects of dihydromyricetin (DHM), a natural flavanol compound, on diabetic retinopathy (DR) and identify its potential mechanisms.

METHODS

Retinal pigment epithelial cell line (ARPE-19) treated with high glucose (HG) was used to simulate the DR model in vitro. After treatment with different concentrations of DHM, the cell viability, production of reactive oxygen species (ROS) and the levels of oxidative stress-related markers in the in vitro model were detected using corresponding kits. Cell apoptosis was determined using terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining, and the expression of apoptotic proteins was examined using Western blot analysis. Subsequently, microRNA (miR)-34a expression was measured by reverse transcription-quantitative PCR (RT-qPCR). The levels of oxidative stress and apoptosis were evaluated after miR-34a overexpression.

RESULTS

Results indicated that DHM dose-dependently elevated the decreased cell viability induced by HG. Moreover, the content of ROS was significantly reduced in HG-stimulated ARPE-19 cells, accompanied by enhanced activities of superoxide dismutase (SOD) and catalase (CAT) antioxidases, as well as concentration of glutathione (GSH). Furthermore, remarkably decreased apoptosis of ARPE-19 cells induced by HG was observed following DHM intervention. Importantly, HG stimulation notably upregulated miR-34a expression, which was reversed by DHM treatment. Importantly, the inhibitory effects of DHM on HG-induced oxidative stress and apoptosis of ARPE-19 cells were restored following miR-34a overexpression.

CONCLUSION

Taken together, this work demonstrated that DHM exerts protective effects on HG-induced oxidative stress and apoptotic damage in ARPE-19 cells via inhibition of miR-34a expression, providing a promising therapeutic agent for the treatment of DR.

Induction of HO-1 by 5, 8-Dihydroxy-4',7-Dimethoxyflavone via Activation of ROS/p38 MAPK/Nrf2 Attenuates Thrombin-Induced Connective Tissue Growth Factor Expression in Human Cardiac Fibroblasts

Heme oxygenase-1 (HO-1) has been shown to exert as an antioxidant and anti-inflammatory enzyme in cardiovascular inflammatory diseases. Flavonoids have been demonstrated to display anti-inflammatory and antioxidant effects through the induction of HO-1. 5,8-Dihydroxy-4',7-dimethoxyflavone (DDF), one of the flavonoid compounds, is isolated from Reevesia formosana. Whether DDF induced HO-1 expression on human cardiac fibroblasts (HCFs) remained unknown. Here, we found that DDF time- and concentration-dependently induced HO-1 protein and mRNA expression, which was attenuated by pretreatment with reactive oxygen species (ROS) scavenger N-acetyl cysteine (NAC) in HCFs. DDF-enhanced ROS generation was attenuated by NAC, but not by either diphenyleneiodonium chloride (DPI, Nox inhibitor) or MitoTempol (mitochondrial ROS scavenger). Interestingly, pretreatment with glutathione (GSH) inhibited DDF-induced HO-1 expression. The ratio of GSH/GSSG was time-dependently decreased in DDF-treated HCFs. DDF-induced HO-1 expression was attenuated by an inhibitor of p38 MAPK (p38i VIII) or siRNA, but not by MEK1/2 (PD98059) or JNK1/2 (SP600125). DDF-stimulated p38 MAPK phosphorylation was inhibited by GSH or p38i VIII. Moreover, DDF-induced HO-1 expression was mediated through Nrf2 phosphorylation and translocation into the nucleus which was attenuated by NAC or p38 siRNA. DDF also stimulated antioxidant response element (ARE) promoter activity which was inhibited by NAC, GSH, or p38i VIII. Interaction between Nrf2 and the ARE-binding sites on the HO-1 promoter was revealed by chromatin immunoprecipitation assay, which was attenuated by NAC, GSH, or p38i VIII. We further evaluated the functional effect of HO-1 expression on the thrombin-induced fibrotic responses. Our result indicated that the induction of HO-1 by DDF can attenuate the thrombin-induced connective tissue growth factor expression. These results suggested that DDF-induced HO-1 expression is, at least, mediated through the activation of the ROS-dependent p38 MAPK/Nrf2 signaling pathway in HCFs. Thus, the upregulation of HO-1 by DDF could be a candidate for the treatment of heart fibrosis.

D-galactose induces senescence of glioblastoma cells through YAP-CDK6 pathway

Treatment of glioblastoma using radiotherapy and chemotherapy has various outcomes, key among them being cellular senescence. However, the molecular mechanisms of this process remain unclear. In the present study, we tested the ability of D-galactose (D-gal), a reducing sugar, to induce senescence in glioblastoma cells. Following pretreatment with D-gal, glioblastoma cell lines (C6 and U87MG) showed typical characteristics of senescence. These included the reduced cell proliferation, hypertrophic morphology, increased senescence-associated β-galactosidase activity, downregulation of Lamin B1, and upregulation of several senescence-associated genes such as p16, p53, and NF-κB. Furthermore, our results showed that D-gal was more suitable than etoposide (a DNA-damage drug) in inducing senescence of glioblastoma cells. Mechanistically, D-gal inactivated the YAP-CDK6 signaling pathway, while overexpression of YAP or CDK6 could restore D-gal-induced senescence of C6 cells. Finally, metformin, an anti-aging agent, activated the YAP-CDK6 pathway and suppressed D-gal-induced senescence of C6 cells. Taken together, these findings established a new model for analyzing senescence in glioblastoma cells, which occurred through the YAP-CDK6 pathway. This is expected to provide a basis for development of novel therapies for the treatment of glioblastoma.