Total flavonoids of Bidens bipinnata L. ameliorate experimental adjuvant-induced arthritis through induction of synovial apoptosis

The protective effects of hyperoside on Ang II-mediated apoptosis of bEnd.3 cells and injury of blood-brain barrier model in vitro

Background

Hypertension and its associated dysfunction of the blood-brain barrier (BBB) are considered to contribute to cerebral small vessel disease (cSVD). Angiotensin II (Ang II), as an important vasoactive peptide of the renin-angiotensin system (RAS), is not only a pivotal molecular signal in hypertension, but also causes BBB leakage, cSVD and its related cognitive impair. Hyperoside (Hyp), a flavone glycoside, has antioxidant, antiphlogistic and anti-apoptosis effects. In this study, we investigate the protection of Hyp on apoptosis of bEnd.3 cells and BBB disruption in vitro induced by Ang II.

Methods

We used bEnd.3 cells to imitate a BBB monolayer model and explored the protection of Hyp on Ang II-induced BBB leakage. The apoptotic activity was assessed by TUNEL staining and flow cytometry. The expression of apoptosis pathway related proteins, tight junction proteins and transcytosis related proteins were detected by western blot assay. The BBB model permeability was detected through measuring the flux of sodium fluorescein (Na-F).

Results

We found that Hyp can not only effectively inhibit the apoptosis of bEnd.3 induced by Ang II, but also protect the structural soundness and functional integrity of BBB model by affecting the expression levels of junctional adhesion molecule A (JAM-A), Claudin-5, zonula occludens-1 (ZO-1), Caveolin-1 (Cav-1) and major facilitator superfamily domain-containing protein 2a (Mfsd2a).

Conclusion

Hyp might be a potent compound for preventing Ang II-induced BBB disruption.

In-vitro examination and isolation of antidiarrheal compounds using five bacterial strains from invasive species Bidens bipinnata L

Bidens bipinnata is widely utilized medicinal plant for treatment of diseases like malaria, sore throat, acute nephritis and dysentery. However, despite its traditional uses Bidens bipinnata is not widely explored for its antimicrobial effect. Thus, the current study is aimed to form antimicrobial activity report of Bidens bipinnata extracts, along with isolation and evaluation of antibacterial activity of the isolated compounds through bioassay-guided purification. Hexane extract of its leaves has appeared to be most active thus it is exposed to automated column chromatography. Further purification using High-performance liquid chromatography has led to isolation of active peaks, identified by Gas Chromatography-mass spectrometry, as 16-Pregnenolone and 9-Octadecenoic acid (Z)-, methyl ester. Their antimicrobial activity was confirmed via broth dilution procedure on Staphylococcus aureus, 16-Pregnenolone revealed a strong antimicrobial activity with MIC₅₀ of 72 μg/mL whereas 9-Octadecenoic acid (Z)-, methyl ester display an MIC₅₀ of >250 μg/mL. Present study is the first report on isolation of these compounds from Bidens bipinnata.

Total Flavonoids of Bidens pilosa Ameliorates Bone Destruction in Collagen-Induced Arthritis

Rheumatoid arthritis is a chronic autoimmune disease characterized by the infiltration of synovial inflammatory cells and progressive joint destruction. Total flavonoids of Bidens pilosa have been used against inflammation in rheumatoid arthritis, but its role in bone destruction remains to be explored. The aim of this paper was to study whether total flavonoids of B. pilosa relieve the severity of collagen-induced arthritis in rats, particularly whether it regulates the production of proinflammatory cytokines and the receptor activator of nuclear factor-κB/receptor activator of nuclear factor-κB ligand/osteoprotegerin signaling pathway. In this research, a collagen-induced disease model was induced in adult rats by subcutaneous injection of collagen II. Total flavonoids of B. pilosa at different doses (40, 80, and 160 mg/kg/d) were administered intragastrically, while methotrexate (1 mg/kg/w) was injected intraperitoneally as a positive control. Paw swelling, arthritis score, and body weight were assessed and evaluated. The severity of joint damage was determined using X-ray and confirmed by histopathology. The expression levels of receptor activator of nuclear factor-κB ligand, osteoprotegerin, IL-1β, IL-17, and TNF in the serum and tissue were assayed using ELISA and immunohistochemistry. We found that total flavonoids of B. pilosa attenuated collagen-induced arthritis at the macroscopic level, and total flavonoids of B. pilosa-treated rats showed reduced paw swelling, arthritis scores, and X-ray appearance of collagen-induced arthritis in addition to improved histopathological results. These findings were consistent with reduced serum and tissue receptor activator of nuclear factor-κB ligand, TNF, IL-1β, and IL-17 levels but increased osteoprotegerin levels. Our data suggest that total flavonoids of B. pilosa attenuate collagen-induced arthritis by suppressing the receptor activator of nuclear factor-κB ligand/receptor activator of nuclear factor-κB/osteoprotegerin pathway and the subsequent production of proinflammatory cytokines. In addition, total flavonoids of B. pilosa may be a promising therapeutic candidate for the management of rheumatoid arthritis.

A sphingosine kinase 2-mimicking TAT-peptide protects neurons against ischemia-reperfusion injury by activating BNIP3-mediated mitophagy

We have previously shown that sphingosine kinase 2 (SPK2) interacts with Bcl-2 via its BH3 domain, activating autophagy by inducing the dissociation of Beclin-1/Bcl-2 complexes, and that a TAT-SPK2 peptide containing the BH3 domain of SPK2 protects neurons against ischemic injury. The goals of the present study were to establish the functional significance of these findings, by testing whether TAT-SPK2 was effective in a mouse model of ischemic stroke, and to explore potential underlying mechanisms. Mice were administered with TAT-SPK2 by intraperitoneal injection before or after transient middle cerebral artery occlusion (tMCAO). Infarct volume, neurological deficit and brain water content were assessed 24 h after reperfusion. Mitophagy inhibitor Mdivi-1 and BNIP3 siRNAs were used to examine the involvement of BNIP3-dependent mitophagy in the neuroprotection of TAT-SPK2. Mitophagy was quantified by immunoblotting, immunofluorescence and electron microscopy. The interaction between TAT-SPK2 and Bcl-2, Bcl-2 and BNIP3 was detected by co-immunoprecipitation. In the tMCAO model, pre-treatment with TAT-SPK2 significantly reduced infarct volume, improved neurological function and decreased brain edema. Neuroprotection by TAT-SPK2 was still seen when the peptide was administered 3 h after reperfusion. TAT-SPK2 also significantly improved functional recovery and reduced long-term brain atrophy of the ischemic hemisphere 30 days after administration. Our studies further showed that TAT-SPK2 directly binds to Bcl-2 and disrupts Bcl-2/Beclin-1 or Bcl-2/BNIP3 complexes to induce mitophagy. These results suggest that TAT-SPK2 protects neurons against ischemia reperfusion injury by activating BNIP3-mediated mitophagy. Agents exploiting this molecular mechanism are potential candidates for the treatment of ischemic stroke.

Overexpression of aquaporin 4 in articular chondrocytes exacerbates the severity of adjuvant-induced arthritis in rats: an in vivo and in vitro study

Background

The dysfunction of articular chondrocytes is a crucial step in rheumatoid arthritis (RA) pathogenesis while its molecular mechanisms are not fully known. This study was aimed to investigate the expression of aquaporin 4 (AQP4) in articular chondrocytes of adjuvant-induced arthritis (AIA) rats and its involvement in AIA development.

Methods

Thirty rats were divided into normal and AIA group (n = 15). Rat AIA was induced by intradermal injection of complete Freund’s adjuvant and evaluated by secondary paw swelling and histological assessments on knee joint damage. Localization and protein expression of AQP4 in articular cartilage were examined by immunohistochemistry and western blot. In vitro study, AIA articular chondrocytes were cultured and treated with acetazolamide, an AQPs inhibitor. AQP4 protein level, cell proliferation and mRNA levels of type-II collagen (COII) and aggrecan were measured by western blot, MTT assay and real-time PCR, respectively.

Results

The results of immunohistochemistry and western blot indicated that AQP4 showed higher protein levels in cartilage tissues of AIA rats than that of normal rats. Correlation analysis revealed that AQP4 protein level in cartilage tissues of AIA rats remarkably correlated positively with secondary paw swelling on day 26 after AIA induction as well as pathological scores on joint damage. Additionally, acetazolamide treatment effectively decreased AQP4 protein level, increased cell proliferation and mRNA levels of COII and aggrecan, suggesting AQP4 inhibition by acetazolamide could normalize the dysfunction of AIA articular chondrocytes in vitro.

Conclusions

Our data provide certain experimental evidence that AQP4 over-expression in articular chondrocytes aggravated AIA severity and might be a novel target for RA treatment.