Green tea polyphenols attenuate LPS-induced inflammation through upregulating microRNA-9 in murine chondrogenic ATDC5 cells

The protective activity of natural flavonoids against osteoarthritis by targeting NF-κB signaling pathway

Osteoarthritis (OA) is a typical joint disease associated with chronic inflammation. The nuclear factor-kappaB (NF-κB) pathway plays an important role in inflammatory activity and inhibiting NF-κB-mediated inflammation can be a potential strategy for treating OA. Flavonoids are a class of naturally occurring polyphenols with anti-inflammatory properties. Structurally, natural flavonoids can be divided into several sub-groups, including flavonols, flavones, flavanols/catechins, flavanones, anthocyanins, and isoflavones. Increasing evidence demonstrates that natural flavonoids exhibit protective activity against the pathological changes of OA by inhibiting the NF-κB signaling pathway. Potentially, natural flavonoids may suppress NF-κB signaling-mediated inflammatory responses, ECM degradation, and chondrocyte apoptosis. The different biological actions of natural flavonoids against the NF-κB signaling pathway in OA chondrocytes might be associated with the differentially substituted groups on the structures. In this review, the efficacy and action mechanism of natural flavonoids against the development of OA are discussed by targeting the NF-κB signaling pathway. Potentially, flavonoids could become useful inhibitors of the NF-κB signaling pathway for the therapeutic management of OA.

Tea Polyphenols Protect the Mammary Gland of Dairy Cows by Enhancing Antioxidant Capacity and Regulating the TGF-β1/p38/JNK Pathway

Tea polyphenols (TPs) are the main active substances in tea and they have many beneficial effects, such as anti-inflammation, antioxidant, anti-cancer and metabolic regulation effects. The quality of milk is affected by mammary gland diseases and there are substantial economic losses resulting from reduced milk production as a consequence of inflammatory injury of the mammary gland. In this study, transcriptome analysis and molecular biology techniques were used to study the effects of TPs on inflammatory injury of the mammary gland. After intervention with TPs, a total of 2085 differentially expressed genes were identified, including 1189 up-regulated genes and 896 down-regulated genes. GO analysis showed that differentially expressed genes played an important role in proton transmembrane transport, oxidation-reduction reactions and inflammatory response. KEGG enrichment suggested that differential genes were concentrated in the TGF-β pathway and active oxygen metabolism process. Experiments were performed to confirm that TPs increased SOD, CAT, T-AOC and GSH-Px content along with a reduction in MDA. Meanwhile, TPs inhibited the expression of TGF-β1 and reduced the phosphorylation of p38 and JNK. The expression of inflammatory cytokines IL-1β, IL-6 and TNF-α were significantly decreased after intervention with TPs. In summary, all the data indicated that TPs protected the mammary gland by enhancing the antioxidant capacity and down-regulating the TGF-β1/p38/JNK pathway.

Crosstalk Among circRNA/lncRNA, miRNA, and mRNA in Osteoarthritis

Osteoarthritis (OA) is a joint disease that is pervasive in life, and the incidence and mortality of OA are increasing, causing many adverse effects on people's life. Therefore, it is very vital to identify new biomarkers and therapeutic targets in the clinical diagnosis and treatment of OA. ncRNA is a nonprotein-coding RNA that does not translate into proteins but participates in protein translation. At the RNA level, it can perform biological functions. Many studies have found that miRNA, lncRNA, and circRNA are closely related to the course of OA and play important regulatory roles in transcription, post-transcription, and post-translation, which can be used as biological targets for the prevention, diagnosis, and treatment of OA. In this review, we summarized and described the various roles of different types of miRNA, lncRNA, and circRNA in OA, the roles of different lncRNA/circRNA-miRNA-mRNA axis in OA, and the possible prospects of these ncRNAs in clinical application.

Effect of nonylphenol on the colonic mucosa in rats and intervention with zinc-selenium green tea (Camellia sinensis)

To investigate the effect of nonylphenol (NP) exposure on the colonic mucosa in rats, and the protective effects of Guizhou zinc-selenium tea (Zn-Se tea) on the damage induced by NP, sixty Sprague-Dawley rats were randomly divided into 6 groups (n = 10 in each group): control group (corn oil), and rats gavaged with NP at the doses of 0.4 mg/kg/d (Low NP group), 4 mg/kg/d (Medium NP group), 40 mg/kg/d (High NP group), and 40 mg/kg NP combined with green tea group at the doses of 0.2 g/ml (NP + GT group) and 0.2 g/ml Zn-Se tea group (NP + ZST group). NP at 40 mg/kg/d was administered to the tea groups for 3 months, followed by NP + green tea and NP + Zn-Se tea for 4 months, and the rest of the groups were gavaged for 7 months. With the increase of NP concentration, NP accumulation in colon gradually increased (P < 0.05), colonic villi shortened, tight junctions between cells widened, intestinal integrity was impaired, and goblet cells, intraepithelial lymphocytes and mast cells were significantly lower in NP high-dose group than in control group (P < 0.05). Meanwhile, the protein expression of Caspase-1, IL-1β and Pro-IL-1β in NP high-dose group was significantly higher than that in control group (P < 0.05). Zn-Se tea increased the number of goblet cells in colon and decreased the accumulation of NP in colon (P < 0.05); Zn-Se tea and common green tea decreased the expression of Caspase-1 and Pro-IL-1β protein (P < 0.05). NP exposure can destroy intestinal morphology, reduce the number of intestinal immune cells, reduce intestinal immunity and increase the release of inflammatory factors; Guizhou Zn-Se tea has a certain protective effect on colon damage caused by NP.

Inhibiting TLR4 signaling by linarin for preventing inflammatory response in osteoarthritis

Osteoarthritis (OA) is one of the most common degenerative diseases, ultimately leading to long-term joint pain and severe articular malformation. Controlling local chronic inflammation is a crucial strategy for delaying OA development. Linarin is a natural flavonoid glycoside that is widely available in Compositae, Chrysanthemum indicum and Dendrocalamus and processes protective effects in several animal models. The purpose of our work was to study the protective effect of Linarin for OA. Cellular experiments data showed that Linarin suppressed lipopolysaccharide (LPS)-caused the overproduction of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in chondrocyte. In addition, LPS-stimulated expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide nitrate (iNOS) was decreased by Linarin pre-treatment. Together, Linarin prevented the catabiosis of extracellular matrix caused by LPS. For mechanism, Linarin inhibited the formation of Toll-like receptor 4 (TLR4) / myeloid differentiation protein-2 (MD-2) dipolymer complex and subsequently intervened NF-κB activation. Our mouse DMM model further clarified the protection of Linarin in vivo. In summary, our results suggested that Linarin may be a potential effective agent for OA.

Nutraceutical Targeting of Inflammation-Modulating microRNAs in Severe Forms of COVID-19: A Novel Approach to Prevent the Cytokine Storm

The coronavirus disease 2019 (COVID-19) pandemic has become the number one health problem worldwide. As of August 2020, it has affected more than 18 million humans and caused over 700,000 deaths worldwide. COVID-19 is an infectious disease that can lead to severe acute respiratory syndrome. Under certain circumstances, the viral infection leads to excessive and uncontrolled inflammatory response, which is associated with the massive release of inflammatory cytokines in pulmonary alveolar structures. This phenomenon has been referred to as the “cytokine storm,” and it is closely linked to lung injury, acute respiratory syndrome and mortality. Unfortunately, there is currently no vaccine available to prevent the infection, and no effective treatment is available to reduce the mortality associated with the severe form of the disease. The cytokine storm associate with COVID-19 shows similarities with those observed in other pathologies such as sepsis, acute respiratory distress syndrome, acute lung injury and other viral infection including severe cases of influenza. However, the specific mechanisms that cause and modulate the cytokine storm in the different conditions remain to be determined. micro-RNAs are important regulators of gene expression, including key inflammatory cytokines involved in the massive recruitment of immune cells to the lungs such as IL1β, IL6, and TNFα. In recent years, it has been shown that nutraceutical agents can modulate the expression of miRs involved in the regulation of cytokines in various inflammatory diseases. Here we review the potential role of inflammatory-regulating-miRs in the cytokine storm associated with COVID-19, and propose that nutraceutical agents may represent a supportive therapeutic approach to modulate dysregulated miRs in this condition, providing benefits in severe respiratory diseases.

Impacts of Green Tea on Joint and Skeletal Muscle Health: Prospects of Translational Nutrition

Osteoarthritis and sarcopenia are two major joint and skeletal muscle diseases prevalent during aging. Osteoarthritis is a multifactorial progressive degenerative and inflammatory disorder of articular cartilage. Cartilage protection and pain management are the two most important strategies in the management of osteoarthritis. Sarcopenia, a condition of loss of muscle mass and strength, is associated with impaired neuromuscular innervation, the transition of skeletal muscle fiber type, and reduced muscle regenerative capacity. Management of sarcopenia requires addressing both skeletal muscle quantity and quality. Emerging evidence suggests that green tea catechins play an important role in maintaining healthy joints and skeletal muscle. This review covers (i) the prevalence and etiology of osteoarthritis and sarcopenia, such as excessive inflammation and oxidative stress, mitochondrial dysfunction, and reduced autophagy; (ii) the effects of green tea catechins on joint health by downregulating inflammatory signaling mediators, upregulating anabolic mediators, and modulating miRNAs expression, resulting in reduced chondrocyte death, collagen degradation, and cartilage protection; (iii) the effects of green tea catechins on skeletal muscle health via maintaining a dynamic balance between protein synthesis and degradation and boosting the synthesis of mitochondrial energy metabolism, resulting in favorable muscle homeostasis and mitigation of muscle atrophy with aging; and (iv) the current study limitations and future research directions.

Nutraceutical Activity in Osteoarthritis Biology: A Focus on the Nutrigenomic Role

Osteoarthritis (OA) is a disease associated to age or conditions that precipitate aging of articular cartilage, a post-mitotic tissue that remains functional until the failure of major homeostatic mechanisms. OA severely impacts the national health system costs and patients' quality of life because of pain and disability. It is a whole-joint disease sustained by inflammatory and oxidative signaling pathways and marked epigenetic changes responsible for catabolism of the cartilage extracellular matrix. OA usually progresses until its severity requires joint arthroplasty. To delay this progression and to improve symptoms, a wide range of naturally derived compounds have been proposed and are summarized in this review. Preclinical in vitro and in vivo studies have provided proof of principle that many of these nutraceuticals are able to exert pleiotropic and synergistic effects and effectively counteract OA pathogenesis by exerting both anti-inflammatory and antioxidant activities and by tuning major OA-related signaling pathways. The latter are the basis for the nutrigenomic role played by some of these compounds, given the marked changes in the transcriptome, miRNome, and methylome. Ongoing and future clinical trials will hopefully confirm the disease-modifying ability of these bioactive molecules in OA patients.