Nyctinastic movement in legumes: Developmental mechanisms, factors and biological significance.

In legumes, a common phenomenon known as nyctinastic movement is observed. This movement involves the horizontal expansion of leaves during the day and relative vertical closure at night. Nyctinastic movement is driven by the pulvinus, which consists of flexor and extensor motor cells. The turgor pressure difference between these two cell types generates a driving force for the bending and deformation of the pulvinus. This review focuses on the developmental mechanisms of the pulvinus, the factors affecting nyctinastic movement, and the biological significance of this phenomenon in legumes, thus providing a reference for further research on nyctinastic movement.

Epoxymicheliolide directly targets histone H2B to inhibit neuroinflammation via recruiting E3 ligase RNF20.

Monoubiquitination plays a critical role as one of the largest histone post-translational modifications (PTMs). Recent study has revealed that histone H2B monoubiquitination (H2Bub1) at a unique lysine 120 (K120) is widely involved in the development of inflammation progression. However, small-molecules directly targeting H2B to exert anti-inflammation effects via editing monoubiquitination have not been hitherto reported. In this study, we first discover a natural small-molecule epoxymicheliolide (ECL), which directly binds to H2B to inhibit microglia-mediated neuroinflammation in vitro and in vivo. Mechanism study suggests that ECL covalently modifies a previously undisclosed lysine 46 (K46) in H2B, and recruits E3 ubiquitin ligase RNF20 to promote H2Bub1 at K120. ChIP-seq and transcriptomics further reveal that ECL-mediated H2Bub1 markedly disrupts the AP-1 recruitment to proinflammatory gene promoters for microglia inactivation. Collectively, our findings suggests that K46 of H2B serves as a promising pharmacological target to develop small-molecule drugs against microglia-mediated neuroinflammation, and ECL represents a valuable lead compound for neuroinflammation via regulating histone monoubiquitination.

Cephalotaxine Inhibits the Survival of Leukemia Cells by Activating Mitochondrial Apoptosis Pathway and Inhibiting Autophagy Flow.

Cephalotaxine (CET) is a natural alkaloid with potent antileukemia effects. However, its underlying molecular mechanism has not been well understood. In this study, we verified that CET significantly inhibited the viability of various leukemia cells, including HL-60, NB4, Jurkat, K562, Raji and MOLT-4. RNA-sequencing and bioinformatics analysis revealed that CET causes mitochondrial function change. Mechanism research indicated that CET activated the mitochondrial apoptosis pathway by reducing the mitochondrial membrane potential, downregulating anti-apoptotic Bcl-2 protein and upregulating pro-apoptotic Bak protein. In addition, the autophagy signaling pathway was highly enriched by RNA-seq analysis. Then, we found that CET blocked the fluorescence colocation of MitoTracker Green and LysoTracker Red and upregulated the level of LC3-II and p62, which indicated that autophagy flow was impaired. Further results demonstrated that CET could impair lysosomal acidification and block autophagy flow. Finally, inhibiting autophagy flow could aggravate apoptosis of HL-60 cells induced by CET. In summary, this study demonstrated that CET exerted antileukemia effects through activation of the mitochondria-dependent pathway and by impairing autophagy flow. Our research provides new insights into the molecular mechanisms of CET in the treatment of leukemia.

[Therapeutic effect and mechanism of Shouhui Tongbian Capsules on slow transit constipation model mice].

Shouhui Tongbian Capsules was used to explore the therapeutic effect and potential mechanism on slow transit constipation model mice induced by loperamide hydrochloride. In the experiment, loperamide hydrochloride-induced ICR mice were used as the model of slow transit constipation. Fifty ICR mice were divided into the blank group, model group and high, medium and low dose groups of Shouhui Tongbian Capsules extract(100, 200 and 400 mg·kg~(-1)). The model group and the administration groups were then modeled using loperamide hydrochloride intragastrically to obtain slow transit constipation. After successful modeling, high, medium and low doses of drugs were given to each drug group by intragastric administration. After 14 days of administration, the first defecation time, 6 h defecation grain number, 6 h defecation wet weight and dry weight, black feces discharged within 6 h and the fecal water content were measured. Intestinal tissues were taken for c-Kit and SCF immunohistochemical sections to detect the expression of c-Kit and SCF in the blank group, model group and high, medium and low dose groups of the medicinal extract of Shouhui Tongbian Capsules. The tissue changes in the intestinal wall of mice were detected by HE staining. At the same time, partial intestinal tissues were taken to test the activity of ATP synthase and isocitrate dehydrogenase in intestinal tissues of mice. RESULTS:: showed that Shouhui Tongbian Capsules effectively improved the symptoms of slow transit constipation in ICR mice and promoted intestinal movement. Shouhui Tongbian Capsules obviously shortened the time of discharging black stool for the first time, improved the intestinal propulsion rate, increased the water content and amount of feces, and improved the constipation symptoms. Mechanism study revealed that Shouhui Tongbian Capsules increased ATP synthase activity and mitochondrial isocitrate dehydrogenase activity in intestinal tissue, and up-regulated c-Kit/SCF signaling pathway to promote interstitial Cajal cells proliferation, intestinal nerve transmission, intestinal motility and transport capacity.

[Molecular mechanism study of Shouhui Tongbian Capsules on promoting energy metabolism of gastrointestinal stromal cells].

Mechanism study was performed to explore how Shouhui Tongbian Capsules promotes energy metabolism of gastrointestinal stromal cells. In this study, gastrointestinal stromal cells line GIST-882 was used as the model to explore energy metabolism regulation effects of Shouhui Tongbian Capsules extract(10, 20, 50 and 100 µg·mL~(-1)) by measuring the cell proliferation, ATP level, mitochondrial membrane potential, and mitochondrial isocitrate dehydrogenase activity. Meanwhile, Western blot was used to detect the proteins expression of SCF/c-Kit and CDK2/cyclin A signaling pathways. Our results showed that Shouhui Tongbian Capsules promoted cell proliferation and increased ATP level of gastrointestinal stromal cells. In addition, Shouhui Tongbian Capsules obviously improved mitochondrial structural integrity, and increased mitochondrial membrane potential in GIST-882 cells. Mechanism study revealed that Shouhui Tongbian Capsules increased mitochondrial isocitrate dehydrogenase activity and up-regulated the proteins expression of SCF/c-Kit and CDK2/cyclin A signaling pathways. Collectively, our study indicated that Shouhui Tongbian Capsules promoted the energy metabolism for gastrointestinal stromal cells proliferation by activating mitochondrial isocitrate dehydrogenase to induce ATP production, as well as activating SCF/c-Kit and CDK2/cyclin A signaling pathways.