Direct activation of tachykinin receptors within baroreflex afferent pathway and neurocontrol of blood pressure regulation

AIM

Substance P (SP) causes vasodilation and blood pressure (BP) reduction. However, the involvement of tachykinin receptors (NKRs) within baroreflex afferent pathway in SP-mediated BP regulation is largely unknown.

METHODS

Under control and hypertensive condition, NKRs' expressions were evaluated in nodose (NG) and nucleus of tractus solitary (NTS) of male, female, and ovariectomized (OVX) rats; BP was recorded after microinjection of SP and NKRs agonists into NG; Baroreceptor sensitivity (BRS) was tested as well.

RESULTS

Immunostaining and immunoblotting data showed that NK1R and NK2R were estrogen-dependently expressed on myelinated and unmyelinated afferents in NG. A functional study showed that BP was reduced dose-dependently by SP microinjection, which was more dramatic in males and can be mimicked by NK1R and NK2R agonists. Notably, further BP elevation and BRS dysfunction were confirmed in desoxycorticosterone acetate (DOCA)-salt model in OVX compared with DOCA-salt model in intact female rats. Additionally, similar changes in NKRs' expression in NG were also detected using DOCA-salt and SHR. Compared with NG, inversed expression profiles of NKRs were also found in NTS with either gender.

CONCLUSION

The estrogen-dependent NKRs' expression in baroreflex afferent pathway participates at least partially in sexual-dimorphic and SP-mediated BP regulation under physiological and hypertensive conditions.

A novel mechanism of mTORC1-mediated serine/glycine metabolism in osteosarcoma development

Osteosarcoma is the major malignant primary bone cancer in children and adolescents, which is highly aggressive with frequent acquisition of chemoresistance phenotypes. Although much progress has been made, mechanisms of osteosarcoma rapid growth and chemoresistance are still not well elucidated. Generally, alternated metabolic characterization has been proposed to be a hallmark of cancer, yet it is lack of a systematic characterization of cancer metabolic networks. In the present study, we aim to characterize osteosarcoma metabolism and key regulators to reveal mechanisms of how osteosarcoma grows and resists apoptosis under stress conditions. The results demonstrate that mTORC1 pathway is hyperactivated in clinical osteosarcoma samples. However, inhibition of mTORC1 may not be enough to induce significant death of osteosarcoma cells. Results of GC-TOFMS suggested that inhibition of mTORC1 reduce one-carbon amino acids, serine and glycine, in osteosarcoma cells. Moreover, mTORC1 regulates serine/glycine de novo synthesis via modulating glycolysis and serine/glycine synthesis gene expressions. Further, mTORC1/serine/glycine metabolic axis promotes osteosarcoma proliferation and antioxidant ability to environmental stress, which finally leads to cell survival. Our results identify a novel mechanism of mTORC1-mediated serine/glycine metabolism as a significant protective system in osteosarcoma cells.

Angelica Sinensis attenuates inflammatory reaction in experimental rat models having spinal cord injury

This study was aimed to evaluate the effect of Angelica Sinensis on experimental rat models in which spinal cord injury was induced by studying different factors. Different factors causing inflammation play a key role in pathophysiology of SCI. Here three groups of rats (n=15, each was used). These included a sham control group where only laminectomy was performed, SCI group where SCI was induced and AS/SCI group where although SCI was induced but Angelica Sinensis was also administered to study its effect and draw a comparison with control. The expression of I-kBα and NF-kB p65 was also studied using western blotting and after recording optical density (OD) values of western blots. MPO activity was used to measure the effect of 20 mg/kg Angelica Sinensis. The levels of proinflammatory cytokines TNF-α, IL-1β and IL-6 were also studied. As compared with SCI group and sham control it was observed that Angelica Sinensis significantly reduced the expression of I-kBα and NF-kB p65, (P<0.05), while MPO activity was also significantly reduced. Proinflammatory cytokine level was also reduced in treated group as compared to both other groups. On the basis of this study we concluded that the use of 20 mg/kg Angelica Sinensis in rat models can attenuate the secondary damage caused by SCI and thus help in controlling the pathology of SCI in rats.