RESUMO
Rho GTPases are essential regulators of the actin cytoskeleton. They are involved in various physiological and biochemical processes such as the regulation of cytoskeleton dynamics, development, proliferation, survival, and regeneration. During the development of cochlear hair cells, Rho GTPases are activated by various extracellular signals through membrane receptors to further stimulate multiple downstream effectors. Specifically, RhoA, Cdc42, and Rac1, members of the classical subfamily of the Rho GTPase family, regulate the development and maintenance of cilia by inducing the polymerization of actin monomers and stabilizing actin filaments. In addition, they also regulate the normal morphology orientation of ciliary bundles in auditory hair cells, which is an important element of cell polarity regulation. Moreover, the actin-related pathways mediated by RhoA, Cdc42, and Rac1 also play a role in the motility of outer hair cells, indicating that the function of Rho GTPases is crucial in the highly polar auditory sensory system. In this review, we focus on the expression of RhoA, Cdc42, and Rac1 in cochlear hair cells and how these small molecules participate in ciliary bundle morphogenesis and cochlear hair cell movement. We also discuss the progress of current research investigating the use of these small molecules as drug targets for deafness treatment.
RESUMO
Sanguisorba officinalis L. (SO), a well-known herbal medicine, has been proven to show effect against thrombocytopenia. However, metabolites of SO in vivo are still unclear, and the underlying mechanism of SO against thrombocytopenia from the aspect of metabolites have not been well elucidated. In this study, an improved analytical method combined with UHPLC-QTOF MS and a molecular network was developed for the rapid characterization of metabolites in vivo based on fragmentation patterns. Then, network pharmacology (NP) was used to elucidate the potential mechanism of SO against thrombocytopenia. As a result, a total of 1678 exogenous metabolites were detected in urine, feces, plasma, and bone marrow, in which 104 metabolites were tentatively characterized. These characterized metabolites that originated from plasma, urine, and feces were then imported to the NP analysis. The results showed that the metabolites from plasma, urine, and feces could be responsible for the pharmacological activity against thrombocytopenia by regulating the PI3K-Akt, MAPK, JAK-STAT, VEGF, chemokine, actin cytoskeleton, HIF-1, and pluripotency of stem cells. This study provides a rapid method for metabolite characterization and a new perspective of underlying mechanism study from the aspect of active metabolites in vivo.
RESUMO
The profiling of natural products is important in modern biological sciences and new drug development. However, the separation and characterization of complex herbal extracts are significantly challenging for researchers in the biochemical field. Herein, an offline two-dimensional mixed-mode liquid chromatography × reversed-phase liquid chromatography system is developed. Our system exhibits high orthogonality and is composed of a newly prepared stationary phase in the first dimension and a traditional C18 phase in the second dimension, and is operated in combination with a high-resolution mass spectrometry and molecular network. Sanguisorba officinalis L. is studied using the proposed method owing to its bioactivity. With the aid of orthogonal separation, the ionization of the individual components is improved. The number of detected compounds and separated peaks are significantly increased when one-dimensional liquid chromatography is upgraded to two-dimensional liquid chromatography. In addition, 270 compounds (127 of which are tentatively characterized as new compounds, and further confirmation is needed) are successfully characterized based on their fragmentation patterns under the guidance of molecular network, while only 95 compounds are characterized using one-dimensional liquid chromatography and high-resolution mass spectrometry. The results indicate that the developed offline two-dimensional mixed-mode liquid chromatography × reversed-phase liquid chromatography, tandem high-resolution mass spectrometry, and molecular network method are effective for profiling complex samples.
