Engineering Glucosamine-6-Phosphate Synthase to Achieve Efficient One-Step Biosynthesis of Glucosamine.

As an important functional monosaccharide, glucosamine (GlcN) is widely used in fields such as medicine, food nutrition, and health care. Here, we report a distinct GlcN biosynthesis method that utilizes engineered Bacillus subtilis glucosamine-6-phosphate synthase (BsGlmS) to convert D-fructose to directly generate GlcN. The best variant obtained by using a combinatorial active-site saturation test/iterative saturation mutagenesis (CAST/ISM) strategy was a quadruple mutant S596D/V597G/S347H/G299Q (BsGlmS-BK19), which has a catalytic activity 1736-fold that of the wild type toward D-fructose. Upon using mutant BK19 as a whole-cell catalyst, D-fructose was converted into GlcN with 65.32% conversion in 6 h, whereas the wild type only attained a conversion rate of 0.31% under the same conditions. Molecular docking and molecular dynamics simulations were implemented to provide insights into the mechanism underlying the enhanced activity of BK19. Importantly, the BsGlmS-BK19 variant specifically catalyzes D-fructose without the need for phosphorylated substrates, representing a significant advancement in GlcN biosynthesis.

Pharmacological basis and new insights of quercetin action in respect to its anti-cancer effects.

Quercetin is a kind of flavonoid compounds that comes from nature and is widely existed in the daily diet. Previous studies have found that quercetin has many effects such as anti-inflammatory, anti-oxidation and anti-cancer. Both in vivo and in vitro experiments have demonstrated that quercetin can exert anti-tumor effects by altering cell cycle progression, inhibiting cell proliferation, promoting apoptosis, inhibiting angiogenesis and metastasis progression, and affecting autophagy. This review summarizes the evidence for the pharmacological potential and inhibition of quercetin on cancers, supporting the viewpoint that quercetin should be adequately considered as a therapeutic agent against various cancers.

SP/NK-1R promotes gallbladder cancer cell proliferation and migration.

Aberrant substance P/neurokinin-1 receptor (SP/NK-1R) system activation plays a critical role in various disorders, however, little is known about the expression and the detailed molecular mechanism of the SP and NK-1R in gallbladder cancer (GBC). In this study, we firstly analyzed the expression and clinical significance of them in patients with GBC. Then, cellular assays were performed to clarify their biological role in GBC cells. Moreover, we investigated the molecular mechanisms regulated by SP/NK-1R. Meanwhile, mice xenografted with human GBC cells were analyzed regarding the effects of SP/NK1R complex in vivo. Finally, patient samples were utilized to investigate the effect of SP/NK-1R. The results showed that SP and NK-1R were highly expressed in GBC. We found that SP strongly induced GBC cell proliferation, clone formation, migration and invasion, whereas antagonizing NK-1R resulted in the opposite effects. Moreover, SP significantly enhanced the expression of NF-κB p65 and the tumor-associated cytokines, while, Akt inhibitor could reverse these effects. Further studies indicated that decreasing activation of NF-κB or Akt diminished GBC cell proliferation and migration. In consistent with results, immunohistochemical staining showed high levels of Akt, NF-κB and cytokines in tumor tissues. Most importantly, the similar conclusion was obtained in xenograft mouse model. Our findings demonstrate that NK-1R, after binding with the endogenous agonist SP, could induce GBC cell migration and spreading via modulation of Akt/NF-κB pathway.

B Vitamins Potentiate Acute Morphine Antinociception and Attenuate the Development of Tolerance to Chronic Morphine in Mice.

OBJECTIVES: Opiate analgesics are the most effective treatments for severe pain, but their clinical utility is often hampered by the development of analgesic tolerance. There are striking similarities between morphine actions and neuropathic pain. We have demonstrated that B vitamins can attenuate neuropathic pain after peripheral nerve injury, sensory neuron inflammation/compression, and transient spinal cord ischemia. Given this similarity, the present study investigated whether B vitamins might be able to modify the antinociceptive effect of morphine as well as morphine tolerance in mice. METHODS: Cell signaling was assayed by Western blot and immunohistochemistry. Antinociception was assessed in ICR mice using the tail flick. The effects of B vitamins on acute morphine-induced antinociception and chronic morphine tolerance were studied. RESULTS: 1) Co-administration of B vitamins with morphine potentiates acute morphine antinociception. 2) B vitamins attenuate the development of antinociceptive tolerance to chronic morphine administration and inhibit morphine-induced p-NR1, p-PKC in the spinal cord. 3) Morphine induces microglial activation, as evidenced by increased p38 MAPK phosphorylation, IBA1, and IL-1ß in the spinal cord, and these changes are inhibited by B vitamins. 4) Treatment of B vitamins alone shows no notable effects on pain threshold and activity of microglia invivo. CONCLUSIONS: B vitamins potentiate acute morphine antinociception and attenuate chronic morphine tolerance.

Inhibition of YAP/TAZ Activity in Spinal Cord Suppresses Neuropathic Pain.

UNLABELLED: Neuropathic pain, often caused by nerve injury, is a major clinical challenge. Mechanisms that underlie neuropathic pain remain elusive and effective medications are limited. Numerous investigations of pain mechanisms have focused on alterations and phenotypic switches of the nociceptive transmitters and modulators, as well as on their receptors and downstream signaling pathways that have already exerted roles in the pain processes of mature nervous systems. We have demonstrated recently that nerve injury may elicit neuronal alterations that recapitulate events occurring during development. Signaling of the representative activated molecule Wnt thus becomes a trigger for the development of neuropathic pain and is a potential therapeutic target. We report that the transcriptional regulators YAP and TAZ, which orchestrate Wnt response via incorporation in the ß-catenin destruction complex, are key in the pathogenesis of neuropathic pain and may serve as an "ON-OFF" switch for neuropathic pain status in rats. Peripheral nerve injury causes rapid-onset and long-lasting nuclear accumulation of YAP/TAZ/ß-catenin in the spinal dorsal horn. Spinal inhibition or knock-down of either YAP or TAZ suppresses mechanical allodynia induced by nerve injury or the pain initiators lysophosphatidic acid and Wnt3a. Promoting the nuclear accumulation of YAP/TAZ leads to mechanical hypersensitivity in naive animals. Further, we discovered a new small molecule, dCTB, which targets YAP/TAZ/ß-catenin and can greatly suppress neuropathic pain and the associated neurochemical alterations. Our study reveals that YAP and TAZ are core mechanisms underlying the pathogenesis of neuropathic pain and are targets in the screening for potent analgesics for the treatment of neuropathic pain. SIGNIFICANCE STATEMENT: Mechanisms that underlie neuropathic pain remain elusive. We have demonstrated recently that nerve injury can activate Wnt signaling, which becomes a trigger for the development of neuropathic pain. We report that the transcriptional regulators YAP and TAZ, which orchestrate Wnt response via incorporation in the ß-catenin destruction complex, are key in the pathogenesis of neuropathic pain and may serve as an "ON-OFF" switch for neuropathic pain status. Further, we discovered a new small molecule, dCTB, which targets YAP/TAZ/ß-catenin and can greatly suppress neuropathic pain. Our study reveals that YAP and TAZ are core mechanisms underlying the pathogenesis of neuropathic pain and are targets in the screening of potent analgesics for the treatment of neuropathic pain.