Histone demethylase JMJD3 downregulation protects against aberrant force-induced osteoarthritis through epigenetic control of NR4A1 / 国际口腔科学杂志·英文版

Osteoarthritis (OA) is a prevalent joint disease with no effective treatment strategies. Aberrant mechanical stimuli was demonstrated to be an essential factor for OA pathogenesis. Although multiple studies have detected potential regulatory mechanisms underlying OA and have concentrated on developing novel treatment strategies, the epigenetic control of OA remains unclear. Histone demethylase JMJD3 has been reported to mediate multiple physiological and pathological processes, including cell differentiation, proliferation, autophagy, and apoptosis. However, the regulation of JMJD3 in aberrant force-related OA and its mediatory effect on disease progression are still unknown. In this work, we confirmed the upregulation of JMJD3 in aberrant force-induced cartilage injury in vitro and in vivo. Functionally, inhibition of JMJD3 by its inhibitor, GSK-J4, or downregulation of JMJD3 by adenovirus infection of sh-JMJD3 could alleviate the aberrant force-induced chondrocyte injury. Mechanistic investigation illustrated that aberrant force induces JMJD3 expression and then demethylates H3K27me3 at the NR4A1 promoter to promote its expression. Further experiments indicated that NR4A1 can regulate chondrocyte apoptosis, cartilage degeneration, extracellular matrix degradation, and inflammatory responses. In vivo, anterior cruciate ligament transection (ACLT) was performed to construct an OA model, and the therapeutic effect of GSK-J4 was validated. More importantly, we adopted a peptide-siRNA nanoplatform to deliver si-JMJD3 into articular cartilage, and the severity of joint degeneration was remarkably mitigated. Taken together, our findings demonstrated that JMJD3 is flow-responsive and epigenetically regulates OA progression. Our work provides evidences for JMJD3 inhibition as an innovative epigenetic therapy approach for joint diseases by utilizing p5RHH-siRNA nanocomplexes.

Role of rate-limiting step of mevalonate pathway in improving lycopene production in Escherichia coli / 生物工程学报

The introduction of the mevalonate pathway (MVA pathway) in recombinant Escherichia coli can improve the synthesis of terpenoids. But the imbalance expression of MVA pathway genes and accumulation of intermediates inhibit cell growth and terpenoids production. In this study, each gene of MVA pathway and key genes of lycopene synthesis pathway were cloned in plasmid to express in the recombinant E. coli LYC103 with optimizing the expression of the key genes of the 2-methyl-D-erythritol-4-phosphate pathway (MEP pathway), chromosome recombinant MVA pathway and the lycopene synthesis pathway. The results showed that the overexpression of ispA, crtE, mvaK1, idi and mvaD genes did not affect the cell growth, while lycopene production increased by 13.5%, 16.5%, 17.95%, 33.7% and 61.1% respectively, indicating that these genes may be the rate-limiting steps for the synthesis of lycopene. mvaK1, mvaK2, mvaD of MVA pathway were the rate-limiting steps and were in an operon. The mvaK1, mvaK2, mvaD operon was regulated by mRS (mRNA stabilizing region) library in front of mvaK1, obtaining strain LYC104. Lycopene yield of LYC104 was doubled and cell growth was increased by 32% compared with the control strain LYC103. CRISPR-cas9 technology was used to integrate idi into chromosome at lacZ site to obtain LYC105 strain. Cell growth of LYC105 was increased by 147% and lycopene yield was increased by 2.28 times compared with that of LYC103. In this study, each gene of lycopene synthesis pathway was expressed in plasmid to certify the rate-limiting gene based on the complete MVA pathway on the chromosome. Then the rate-limiting gene was integrated in chromosome with homologous recombination to release the rate-limiting, which providing a new strategy for the construction of high-yield strains for metabolic engineering.

Pharmacokinetics/Pharmacodynamics models of veterinary antimicrobial agents

Misuse and abuse of veterinary antimicrobial agents have led to an alarming increase in bacterial resistance, clinical treatment failure, and drug residues. To address these problems, consistent and appropriate dosage regimens for veterinary antimicrobial agents are needed. Pharmacokinetics/Pharmacodynamics (PK/PD) models have been widely used to establish rational dosage regimens for veterinary antimicrobial agents that can achieve effective prevention and treatment of bacterial diseases and avoid the development of bacterial resistance. This review introduces building methods for PK/PD models and describes current PK/PD research progress toward rational dosage regimens for veterinary antimicrobial agents. Finally, the challenges and prospects of PK/PD models in the design of dosage regimens for veterinary antimicrobial agents are reviewed. This review will help to increase awareness of PK/PD modeling among veterinarians and hopefully promote its development and future use.

Integrating balanced mevalonate pathway into chromosome for improving lycopene production in Escherichia coli / 生物工程学报

Isoprenoids are all derived from two five-carbon building blocks called isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), which are synthesized either by the mevalonate (MVA) pathway or 2-C-methyld-D-erythritol-4-phosphate (MEP) pathway. In this study, the MVA pathway genes were integrated into the chromosome of LYC101, in which the expression of key genes in the MEP synthesis pathway and lycopene synthesis pathway were optimized by artificial regulatory parts, to further improve the production of isoprenoids in Escherichia coli. The plasmids pALV23 and pALV145 were screened from a plasmid library that constructed by using the RBS library to link the genes of the MVA pathway, which greatly increased the production of β-carotene. The effects of plasmids pALV23 and pALV145 on the lycopene production in low and high lycopene production strain, LYC001 and LYC101, were compared, respectively. The production of lycopene was increased by plasmids pALV23 and pALV145 in both strains. In high lycopene production strain LYC101, pALV23 produced more lycopene than pALV145. Then, the MVA gene together of promoter of pALV23 was integrated into the chromosome of LYC101 at poxB site using method of homologous recombination helped by CRISPR-Cas9 system, resulted in genetically stable strain, LYC102. The yield of lycopene of LYC102 was 40.9 mg/g DCW, 1.19-folds higher than that of LYC101, and 20% more than that of LYC101 with pALV23. Simultaneous expression of MVA pathway and MEP pathway in recombinant E. coli can effectively increase the yield of terpenoids. In this study, a plasmid-free, genetically stable, high-yielding lycopene strain was constructed, which could be used for industrialization. Also, the platform strain can be used for the synthesis of other terpenoids.

A review of current research on case-based learning in midwifery / 中国实用护理杂志

In this review,we have briefly described the case-based learning about its history,development,characteristics,effect,status quo at home and abroad,the problem in the application in our country.More,we have focused on how the case-based learning is carried out and what the scope is in midwifery both domestic and overseas,the aim is to promote the reform of the midwifery in China and to train qualified midwives.