Identification of a cytochrome P450 from Tripterygium hypoglaucum (Levl.) Hutch that catalyzes polpunonic acid formation in celastrol biosynthesis.

Tripterygium hypoglaucum (Levl.) Hutch, a traditional Chinese medicinal herb with a long history of use, is widely distributed in China. One of its main active components, celastrol, has great potential to be developed into anti-cancer and anti-obesity drugs. Although it exhibits strong pharmacological activities, there is a lack of sustainable sources of celastrol and its derivatives, making it crucial to develop novel sources of these drugs through synthetic biology. The key step in the biosynthesis of celastrol is considered to be the cyclization of 2,3-oxidosqualene into friedelin under the catalysis of 2,3-oxidosqualene cyclases. Friedelin was speculated to be oxidized into celastrol by cytochrome P450 oxidases (CYP450s). Here, we reported a cytochrome P450 ThCYP712K1 from Tripterygium hypoglaucum (Levl.) Hutch that catalyzed the oxidation of friedelin into polpuonic acid when heterologously expressed in yeast. Through substrate supplementation and in vitro enzyme analysis, ThCYP712K1 was further proven to catalyze the oxidation of friedelin at the C-29 position to produce polpunonic acid, which is considered a vital step in the biosynthesis of celastrol, and will lay a foundation for further analysis of its biosynthetic pathway.

Metabolic Engineering of Saccharomyces cerevisiae for High-Level Friedelin via Genetic Manipulation.

Friedelin, the most rearranged pentacyclic triterpene, also exhibits remarkable pharmacological and anti-insect activities. In particular, celastrol with friedelin as the skeleton, which is derived from the medicinal plant Tripterygium wilfordii, is a promising drug due to its anticancer and antiobesity activities. Although a previous study achieved friedelin production using engineered Saccharomyces cerevisiae, strains capable of producing high-level friedelin have not been stably engineered. In this study, a combined strategy was employed with integration of endogenous pathway genes into the genome and knockout of inhibiting genes by CRISPR/Cas9 technology, which successfully engineered multiple strains. After introducing an efficient TwOSC1T502E, all strains with genetic integration (tHMG1, ERG1, ERG20, ERG9, POS5, or UPC2.1) showed a 3.0∼6.8-fold increase in friedelin production compared with strain BY4741. Through further double knockout of inhibiting genes, only strains GD1 and GD3 produced higher yields. Moreover, strains GQ1 and GQ3 with quadruple mutants (bts1; rox1; ypl062w; yjl064w) displayed similar increases. Finally, the dominant strain GQ1 with TwOSC1T502E was cultured in an optimized medium in shake flasks, and the final yield of friedelin reached 63.91 ± 2.45 mg/L, which was approximately 65-fold higher than that of the wild-type strain BY4741 and 229% higher than that in ordinary SD-His-Ura medium. It was the highest titer for friedelin production to date. Our work provides a good example for triterpenoid production in microbial cell factories and lays a solid foundation for the mining, pathway analysis, and efficient production of valuable triterpenoids with friedelin as the skeleton.

[Purification and characterization of the proliferation of rat osteoblast-like cells UMR-106 from pilose antler].

OBJECTIVE: The activity of deer serum albumin on proliferation of rat osteogenic-like cells UMR-106 and the IGF-I secretion were investigated in order to elucidate pilose antler's bone-strengthening mechanism. METHOD: Deer serum albumin was isolated from freeze-dry pilose antler powder extract. The methods were Sephacryl S-200HR gel filtration, POROS 20QE ion-exchange and TSK G3000SW chromatographies. The effect of deer serum albumin on proliferatio of UMR-106 cells was assaied by MTT, and the secretion of IGF-I of UMR-106 cells was assaied by RIA. RESULT: Deer serum albumin, with the molecular weight of 56.3 kDa, significantly increased the proliferation rate of the osteoblast-like UMR-106 cell and IGF-I secretion. When concentration of deer serum albumin reached 0.149 microg x mL(-1), UMR-106 cell proliferation rate was 241.03% and IGF-I secretion was 66.89 ng x mL(-1). CONCLUSION: The concentration of deer serum albumin, from 14.9 ng x mL(-1) to 14.90 microg x mL(-1), significantly increased the proliferation rate of the osteoblast-like UMR-106 cell and IGF- I secretion.

[The modulation of pilose antler extract (PAE) on the proliferation of rat osteogenic cells UMR-106].

OBJECTIVE: To investigate the modulation of pilose antler extract (PAE) on rat osteogenic cells UMR-106 in vitro. METHOD: Component P2 of PAE was isolated by Sephacryl S-200HR gel filtration chromatography. The proliferative effects of P2 and other components isolated by Sephacryl S-200HR on UMR-106 cells were investigated by MTT assay. RESULT: The P2 could significantly increase the proliferation rate of osteogenic cells. When the protein concentration of P2 was between 0.972 mg x L(-1) and 97.2 mg x L(-1), it could inhibit the proliferation of UMR-106 cells. But while the concentration was equal to or greater than 97.2 mg x L(-1), the P2 could increase the proliferation rate of cells, especially 477.92% at 9.72 g x L(-1), which was approximated to 499.62% of PAE. The molecular weight of the P2 was about 59 kDa determined by SDS-PAGE. On the other hand, inhibition was also observed in the sample of the P3, P4 and P5. CONCLUSION: Those regulative factors in PAE which have different molecular weight can affect the proliferation of UMR-106 cells two-wayly. And this adjustment also relies on the dose of those factors. This finding may help us to understand the possible mechanism of Chinese traditional medicine from animal materials.