Novel Leflunomide Analog, UTLOH-4e, Ameliorates Gouty Arthritis Induced by Monosodium Urate Via NF-κB/NLRP3 Signaling Pathway.

BACKGROUND: Gouty arthritis (GA) is a common form of inflammatory arthritis caused by intra-articular deposition of monosodium urate (MSU) crystals; however, there is a tremendous lack of safe and effective therapy in the clinic. OBJECTIVE: The goal of this work was to investigate a novel leflunomide analogue, N-(2,4- dihydroxyphenyl)-5-methyl-1,2-oxazole-3-carboxamide (UTLOH-4e), for its potential to prevent/ treat gouty arthritis. METHODS: In this study, the anti-inflammatory activity of UTLOH-4e was evaluated by MSUinduced GA model in vivo and in vitro, and the molecular docking test was applied to estimate the affinity of UTLOH-4e/UTL-5g/b for MAPKs, NF-κB, and NLRP3. RESULTS: In vitro, UTLOH-4e (1~100 µM) treatment inhibited the inflammatory reaction with no obvious cytotoxicity in PMA-induced THP-1 macrophages exposed to MSU crystals for 24 h, involving the prominent decreased production and gene expression of IL-1ß, TNF-α, and IL-6. Western blot analyses demonstrated that UTLOH-4e (1~100 µM) significantly suppressed the activation of NLRP3 inflammasomes, NF-κB, and MAPK pathways. Furthermore, the data from the experiment on gouty rats induced by intra-articular injection of MSU crystal confirmed that UTLOH-4e markedly ameliorated rat paw swelling, articular synovium inflammation and reduced the concentration of IL-1ß and TNF-α in serum through down-regulating NLRP3 protein expression. CONCLUSION: These results manifested that UTLOH-4e ameliorates GA induced by MSU crystals, which contributes to the modulation of NF-κB/ NLRP3 signaling pathway, suggesting that UTLOH- 4e is a promising and potent drug candidate for the prevention and treatment of gouty arthritis.

Berberine prevents diabetic retinopathy through inhibiting HIF-1α /VEGF/ NF-κ B pathway in db/db mice.

Our paper investigated the effect of berberine on the diabetic retinopathy (DR) in db/db transgenic mice and explored its possible mechanisms. During chronic intragastric administration for ten weeks, berberine could decrease the levels of fasting blood glucose, TC and TG without hepatotoxicity. Moreover, berberine could protect the retinal morphology against the hyperglycemic insults and decrease glycogen accumulation, the contents of TNF-α and IL-1ß in the retinas, as demonstrated by HE staining, PAS staining and ELISA kits, respectively. Immunofluorescence assay revealed that the protein expression of vascular endothelial growth factor (VEGF), VEGF receptor 2, hypoxia-inducible factor-1α(HIF-1α), and nuclear factor-κ B (NF-κB) p65 was upregulated in db/db retinas compared with wild type ones, whereas berberine treatment could suppress their expression. Berberine prevent DR development through modulating the glucolipid metabolism and inhibiting the HIF-1α /VEGF/NF-κ B pathway, suggesting that berberine maybe a potential agent for the treatment of DR.

Tetrahydrocurcumin ameliorates diabetes profiles of db/db mice by altering the composition of gut microbiota and up-regulating the expression of GLP-1 in the pancreas.

Diabetes is a worldwide healthy concern, which affects approximately 9% of the population. Tetrahydrocurcumin (THC) is the main metabolite of curcumin, which exerts the anti-diabetic activity. However, the underlying mechanism has not been clarified. In the research, we investigated whether THC could improve diabetes by regulating the gut microbiota and the expression of pancreatic glucagon-like peptide-1 (GLP-1) in the db/db mice. After 8-week THC administration (ig., once a day, THCH group: 200 mg/kg, THCL group: 100 mg/kg), the fasting blood glucose (FBG) was measured every two weeks. Serum insulin levels, the expression of GLP-1 in the pancreas, the histopathology of pancreas and the composition of gut microbiota were evaluated at the end of the experiment. Compared to the diabetic group, THC treatment decreased significantly blood glucose, increased the secretion of insulin and the expression of GLP-1 in the pancreas. Histomorphological analysis revealed that THC could protect pancreatic islet cells against hyperglycemic insult. Furthermore, the data from the sequencing of the 16S rDNA genes in gut microbiome displayed that THC could restore the intestinal dysbiosis, including the lowered relative abundance of Proteobacteria, Actinobacteria and the ratio of Firmicutes to Bacteroidetes. The linear regression analysis showed a close correlation between the GLP-1 expression and the proportion of the intestinal microflora. Altogether, these results demonstrated that THC might have a direct regulatory effect on gut microflora, which indirectly decrease the FBG levels by modulating GLP-1 expression in the pancreas.