An Engineered Imine Reductase for Highly Diastereo- and Enantioselective Synthesis of ß-Branched Amines with Contiguous Stereocenters.

ß-Branched chiral amines with contiguous stereocenters are valuable building blocks for preparing various biologically active molecules. However, their asymmetric synthesis remains challenging. Herein, we report a highly diastereo- and enantioselective biocatalytic approach for preparing a broad range of ß-branched chiral amines starting from their corresponding racemic ketones. This involves a dynamic kinetic resolution-asymmetric reductive amination process catalyzed using only an imine reductase. Four rounds of protein engineering endowed wild-type PocIRED with higher reactivity, better stereoselectivity, and a broader substrate scope. Using the engineered enzyme, various chiral amine products were synthesized with up to >99.9% ee, >99:1 dr, and >99% conversion. The practicability of the developed biocatalytic method was confirmed by producing a key intermediate of tofacitinib in 74% yield, >99.9% ee, and 98:2 dr at a challenging substrate loading of 110 g L-1. Our study provides a highly capable imine reductase and a protocol for developing an efficient biocatalytic dynamic kinetic resolution-asymmetric reductive amination reaction system.

[Effects of Sophora japonica extract on alveolar bone mass in ovariectomized osteoporosis mice].

PURPOSE: To investigate the effect of Sophora japonica extract on alveolar bone mass in ovariectomized osteoporosis mice. METHODS: Six-week-old female non-pregnant wild-type C57BL/6J mice were randomly divided into sham operation group, ovariectomy(OVX) group and OVX+Sophora japonica extract group. Ovaries of the mice in the OVX group and the OVX+Sophora japonica extract group were removed, and the mice in the OVX+Sophora japonica extract group were treated by Sophora japonica extract at a dose of 150 mg/kg, three times a week for 4 weeks; while mice of the other two groups were given an equal volume of normal saline at the same time. Body weight was measured 3 times a week, and the micro-parameters of alveolar bone were detected by Micro-CT after 4 weeks. The data were analyzed by GraphPad Prism 9 software. RESULTS: Compared with the sham-operated group, the trabecular bone parameters of the alveolar bone in the OVX group were significantly decreased 1 month after operation (P＜0.05). One month after intervention with Sophora japonica extract, alveolar bone mineral density (BMD), trabecular number (Tb.N) and trabecular separation(Tb.Sp) in OVX mice was significantly rescued, with no significant difference compared to the sham surgery group(P＞0.05); but bone volume fraction(BV/TV) and trabecular thickness (Tb.Th) had not completely recovered to the levels of the sham-operated group(P＜0.05). CONCLUSIONS: Sophora japonica extract can effectively increase the alveolar bone mass reduced by estrogen deficiency and may be used as one of the potential drugs for the treatment of menopausal alveolar bone osteoporosis.

Rational design and synthesis of triazene-amonafide derivatives as novel potential antitumor agents causing oxidative damage towards DNA through intercalation mode.

In this work, we rationally designed and synthesized two novel triazene-amonafide derivatives 2-(2-(diisopropylamino)ethyl)-5-(3,3-dimethyltriaz-1-en-1-yl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (D-11) and 5-(3,3-diethyltriaz-1-en-1-yl)-2-(2-(diisopropylamino)ethyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (D-12) as potential antitumor agents. The DNA damage induced by the intercalation mode of D-11 (D-12) towards DNA was electrochemically detected through the construction of efficient biosensors. The consecutive processes of reversible redox of naphthylimide ring and irreversible oxidation of triazene moiety were elucidated on the surface of glassy carbon electrode (GCE) by CV, SWV, and DPV methods. Electrochemical biosensors were obtained through the immobilization of ctDNA, G-quadruplexes, poly(dG), and poly(dA), respectively, on the clean surface of GCE. After the incubation of biosensors with D-11 or D-12, the peaks of dGuo and dAdo decreased prominently, and the peak of 8-oxoGua appeared at +0.50 V, suggesting that the interaction between D-11 (D-12) and DNA could result in the oxidative damage of guanine. Unexpected, the as-prepared DNA biosensor possessed satisfactory anti-interference property and good practicability in real samples. UV-vis and fluorescence spectra, and gel electrophoresis assays were employed to further confirm the intercalation mode of D-11 (D-12) towards DNA base pairs. Moreover, D-11 was proved to exhibit stronger anti-proliferation activity than mitionafide and amonafide against both A549 and HeLa cell lines.

Age at first birth is associated with the likelihood of frailty in middle-aged and older women: A population-based analysis from NHANES 1999-2018.

OBJECTIVES: This study examined whether age at first birth (AFB) is associated with the prevalence of frailty in middle-aged and older women. METHODS: The study included 10,828 women (age ≥ 45 years) from the National Health and Nutrition Examination Survey (NHANES) (1999-2018) in the United States. AFB data were collected using a standardized reproductive health questionnaire. Frailty was measured using a 53-item frailty index and was diagnosed if the score on that index was over 0.21. Survey-weighted logistic regression models were used to assess the association between AFB and the prevalence of frailty. A survey-weighted restricted cubic spline (RCS) model was used to determine the dose-response relationship between AFB and frailty. Mediation analyses were performed to estimate the mediated effects of education levels, family poverty income ratio, and parity on the association between AFB and the likelihood of frailty. Finally, sensitivity and subgroup analyses were conducted to validate the robustness of our findings. RESULTS: Among the 10,828 women, 3828 (35.4 %) had frailty. The RCS depicted a U-shaped association between AFB and frailty. Compared with the women in the reference group (AFB: 33-35 years), women in the other groups (AFB: < 18, 18-20, 21-23, and 24-26 years) had a higher likelihood of frailty, with respective odds ratios (95 % confidence intervals) of 3.02 (1.89-4.83), 2.32 (1.54-3.50), 1.83 (1.19-2.81), and 1.64 (1.07-2.53). However, no statistically significant differences were detected for women with AFB of 27-29, 30-32, or > 35 years compared with the reference group. Education levels, family poverty income ratio, and parity significantly mediated the approximately linear negative association between AFB and frailty in the subset of women with AFB of ≤32 years and the mediation proportions were 23.4 %, 32.4 %, and 18.3 %, respectively (all p < 0.001). CONCLUSIONS: Based on our results, we conclude that early AFB is associated with a higher likelihood of frailty in middle-aged and older women.