ABSTRACT
Objective:To compare the quality of Astragali Radix at different harvest time; To revise the content determination indexes of Astragali Radix in Chinese Pharmacopoeia. Methods:An Agilent Eclipse XDB-C18 column (4.6 mm × 150 mm, 5 μm) was used for the determination of saponins with acetonitrile-water solution as mobile phase in a gradient mode. The drift tube temperature of ELSD was 60 ℃; the pressure was 30 psi; the gain was 800 ℃; the flow rate was 1.0 ml/min; the column temperature was 30 ℃; the injection volume was 20 μl; the acetonitrile-0.2% formic acid solution was used as mobile phase for the determination of flavonoids in a gradient mode; the flow rate was 1.0 ml/min; the detection wavelength was 260 nm; the column temperature was 30 ℃; the 10 μl was injected. The limited range as an indicator for determining Astragali Radix content was determined by investigating the extraction method and extraction time of Astragaloside Ⅰ and detecting the content of Astragaloside Ⅰ in 12 batches of Astragali Radix from different origins. The moisture, total ash, and water-soluble extracts in Astragali Radix were determined according to the drying method, total ash determination method, and cold soaking method in the four parts of Chinese Pharmacopoeia (2020 edition), respectively. Results:The content of total saponins in Astragali Radix harvested in spring and autumn in different origins was not significantly different, but the content of total flavonoids was significantly different. Except for H11, the content of Astragaloside Ⅰ in the other batches of Astragali Radix was ≥ 0.05%, so the content limit of Astragaloside Ⅰ was proposed to be≥0.05%. The results of moisture, total ash and water-soluble extracts in the 12 batches of Astragali Radix all meet the requirements in the Chinese Pharmacopoeia. Conclusions:Astragali Radix harvested in autumn is with higher content of active components and better quality. At the same time, this study can provide a reference that the new version of Chinese Pharmacopoeia can revise the Astragaloside Ⅳ in the content determination index of Astragali Radix to Astragaloside Ⅰ .
ABSTRACT
Primitive mammalian heart transforms from a single tube to a four-chambered muscular organ during a short developmental window. We found that knocking out global microRNA by deleting Dgcr8 microprocessor in Mesp1 cardiovascular progenitor cells lead to the formation of extremely dilated and enlarged heart due to defective cardiomyocyte (CM) differentiation. Transcriptome analysis revealed unusual upregulation of vascular gene expression in Dgcr8 cKO hearts. Single cell RNA sequencing study further confirmed the increase of angiogenesis genes in single Dgcr8 cKO CM. We also performed global microRNA profiling of E9.5 heart for the first time, and identified that miR-541 was transiently highly expressed in E9.5 hearts. Interestingly, introducing miR-541 back into microRNA-free CMs partially rescued their defects, downregulated angiogenesis genes and significantly upregulated cardiac genes. Moreover, miR-541 can target Ctgf and inhibit endothelial function. Our results suggest that microRNAs are required to suppress abnormal angiogenesis gene program to maintain CM differentiation.
ABSTRACT
Embryonic and induced pluripotent stem cells (ESCs and iPSCs) hold great promise for regenerative medicine. The therapeutic application of these cells requires an understanding of the molecular networks that regulate pluripotency, differentiation, and de-differentiation. Along with signaling pathways, transcription factors, and epigenetic regulators, microRNAs (miRNAs) are emerging as important regulators in the establishment and maintenance of pluripotency. These tiny RNAs control proliferation, survival, the cell cycle, and the pluripotency program of ESCs. In addition, they serve as barriers or factors to overcome barriers during the reprogramming process. Systematic screening for novel miRNAs that regulate the establishment and maintenance of pluripotent stem cells and further mechanistic investigations will not only shed new light on the biology of ESCs and iPSCs, but also help develop safe and efficient technologies to manipulate cell fate for regenerative medicine.