Agonistic activity of tamoxifen, a selective estrogen-receptor modulator (SERM), on arthritic ovariectomized mice

Estrogen markedly reduces circulating low-density neutrophils and enhances pro-tumoral gene expression in neutrophil of tumour-bearing mice

Background

Neutrophils are important for immune surveillance of tumour cells. Neutrophils may also be epigenetically programmed in the tumour microenvironment to promote tumour progression. In addition to the commonly known high-density neutrophils (HDN) based on their separation on density gradient, recent studies have reported the presence of high levels of low-density neutrophils (LDN) in tumour-bearing mice and cancer patients. We reported previously that estrogen promotes the growth of estrogen receptor α-negative mammary tumours in mice undergoing mammary involution through stimulating pro-tumoral activities of neutrophils in the mammary tissue.

Methods

Female BALB/cAnNTac mice at 7–8 weeks old were mated and bilateral ovariectomy was performed 2 days post-partum. At 24 h after forced-weaning of pups to induce mammary involution, post-partum female mice were injected with either E2V, or vehicle control on alternative days for 2-weeks. On 48 h post-weaning, treated female mice were inoculated subcutaneously with 4 T1-Luc2 cells into the 9th abdominal mammary gland. Age-matched nulliparous female was treated similarly. Animals were euthanized on day 14 post-tumour inoculation for analysis. To evaluate the short-term effect of estrogen, post-partum females were treated with only one dose of E2V on day 12 post-tumour inoculation.

Results

Estrogen treatment for 2-weeks reduces the number of blood LDN by more than 10-fold in tumour-bearing nulliparous and involuting mice, whilst it had no significant effect on blood HDN. The effect on tumour-bearing mice is associated with reduced number of mitotic neutrophils in the bone marrow and increased apoptosis in blood neutrophils. Since estrogen enhanced tumour growth in involuting mice, but not in nulliparous mice, we assessed the effect of estrogen on the gene expression associated with pro-tumoral activities of neutrophils. Whilst 48 h treatment with estrogen had no effect, 2-weeks treatment significantly increased the expression of Arg1, Il1b and Tgfb1 in both HDN and LDN of involuting mice. In contrast, estrogen increased the expression of Arg1 and Ccl5 in HDN and LDN of nulliparous mice.

Conclusions

Prolonged estrogenic stimulation in tumour-bearing mice markedly hampered tumour-associated increase of LDN plausibly by inhibiting their output from the bone marrow and by shortening their life span. Estrogen also alters the gene expression in neutrophils that is not seen in tumour-free mice. The results imply that estrogen may significantly influence the tumour-modulating activity of blood neutrophils.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08751-2.

Nerolidol-beta-cyclodextrin inclusion complex enhances anti-inflammatory activity in arthritis model and improves gastric protection

Rheumatoid arthritis is an autoimmune inflammatory disease with progressive degradation of cartilage and joints. Additionally, gastric ulcer affects many patients who make prolonged use of non-steroidal anti-inflammatory drugs widely used in the symptomatic treatment of rheumatoid arthritis. Nerolidol, a natural sesquiterpene, has several biological activities including anti-inflammatory and antiulcerogenic action. This study aims to develop and characterize a nerolidol ß-cyclodextrin inclusion complex and to evaluate its activity in an experimental arthritis model. Inclusion complex was prepared by the lyophilization method and characterized by NMR, term analysis, XRD and SEM. Neutrophil migration assays and histopathological analysis were performed on zymosan-induced arthritis model using Swiss mice. And the gastroprotective effect was evaluated in two models of gastric ulcers: induced by ethanol and indomethacin. Inclusion complex showed no cytotoxicity and free nerolidol at a dose of 100 mg/kg (p.o.) in the arthritis model reduced neutrophil migration in 56% in relation to vehicle, and this inhibition was more expressive in the inclusion complex (67%) at the same dose. Histopathological analysis of the joint tissue confirmed the reduction of inflammatory signs. In the ethanol-induced gastric ulcer model, free nerolidol reduced the relative ulcer area more expressively (4.64%) than the inclusion complex (21.3%). However, in the indomethacin induction model, the inclusion complex showed better results in gastric protection compared to free nerolidol. The action of nerolidol complexed in beta-cyclodextrin in reducing arthritis inflammation combined with its gastroprotective action make it a potential new drug.

Anti-inflammatory effect of nano-encapsulated nerolidol on zymosan-induced arthritis in mice

Nerolidol is naturally occurring sesquiterpene has wide range of biological properties including anti-inflammatory activity. However, it has high volatility with low solubility in nature. The present study aimed to develop and characterized nano-encapsulated nerolidol and evaluated its activity on zymosan-induced arthritis model. Nano-capsules were produced by interfacial deposition of preformed polymer method and characterized by particle size, pH, polydispersity index (PDI), zeta potential, drug content and transmission electron microscopy (TEM). In vitro cytotoxicity of formulations was evaluated by alamar blue and MTT assays. In vivo neutrophils migration assay was performed on intra-articular zymosan-induced arthritis model in mice. Nano-encapsulated nerolidol suspensions presented adequate properties: mean diameter of particles 219.5 ± 8.4 nm, pH: 6.84 ± 0.5, PDI≤0.2, the zeta potential was -20.3 ± 3.6 mV and drug content 71,2 ± 1.3%. The formulations did not demonstrated cytotoxicity under the conditions assessed. Nerolidol 300 mg/kg inhibited neutrophils migration into joint cavity by 18.8% remains compared with control group, and nano-encapsulated nerolidol 3 mg/kg inhibited (26.7% remains) similar to free nerolidol 10 mg/kg (27.4% remains). Histological, quantification of pro-inflammatory and anti-inflammatory cytokines proves the same results. In conclusion the data suggests that nanoencapsulation of nerolidol improved its anti-inflammatory effect on arthritis in mice.

Estradiol replacement therapy regulates innate immune response in ovariectomized arthritic mice

Neuroendocrine changes are essential factors contributing to the progression and development of rheumatoid arthritis. However, the role of estrogen in the innate immunity during arthritis development is still controversial. Here, we evaluated the effect of estrous cycle, ovariectomy, estradiol replacement therapy and treatment with estrogen receptor (ER)α and ERβ specific agonists on joint edema formation, neutrophil recruitment, and articular levels of cytokines/chemokines in murine zymosan-induced arthritis. Our results showed that articular inflammation of proestus/estrus was similar to metaestus/diestrus animals indicating that the inflammatory response in acute arthritis is not affected by the estrous cycle. However, ovariectomy increased joint swelling, neutrophil migration, and TNF-α level. Treatment for six consecutive days with estradiol cypionate re-established the acute inflammation in ovariectomized arthritic mice to responses similar to those in SHAM-proestrus/estrus or naive mice. Moreover, treatment with propylpyrazoletriol and diarylpropionitrile, two ERα and ERβ selective agonists, respectively, inhibited both edema and neutrophil recruitment. Finally, the non-genomic properties of estradiol were analyzed with an acute treatment with β-estradiol-water soluble, which reduced the edema only. In the present study, estradiol replacement therapy improves the innate immune responses in ovariectomized arthritic mice by activating nuclear estrogen receptors. These results suggest that estradiol can induce a protective anti-inflammatory effect in arthritis during ovaries failure, as observed in the menopause.