Effects of Waterlogging Stress on the Physiological Characteristics and Secondary Metabolites of Herbaceous Peony (<i>Paeonia lactiflora</i>Pall.)

Herbaceous peony is an ornamental plant with medicinal properties. Waterlogging can affect its yield and quality as it grows and matures. In this study, we subjected “Taohuafeixue”, “Yangfeichuyu” and “Hongxiuqiu” herbaceous peony varieties to a simulated waterlogging stress treatment and investigated the effects of waterlogging on their physiological characteristics and the secondary metabolite contents in their leaves and roots. Short-term waterlogging caused the leaves to turn yellow or red and the roots to turn black. The stele and the cell wall of the endothelial cells thickened, and the cortical cells enlarged. Waterlogging did not significantly change plant height, leaf length, and leaf area;however, it significantly decreased the root-shoot ratio of “Yangfeichuyu” and “Hongxiuqiu” varieties. The activity of antioxidant enzymes and the content of osmotic regulators increased under waterlogging. After short-term waterlogging stress treatment, the content of paeoniflorin and albiflorin increased in the roots of “Taohuafeixue” and “Yangfeichuyu”, and the content of benzoylpaeoniflorin increased in the root of “Hongxiuqiu”. The content of gallic acid and total flavonoids increased in the leaves of “Taohuafeixue” and “Yangfeichuyu”. After the waterlogging, paeoniflorin and benzoylpaeoniflorin increased in the autumn root of “Hongxiuqiu”. This study expands our knowledge about the medicinal properties of herbaceous peony and informs about its production and cultivation under waterlogged conditions.

Single-cell RNA sequencing reveals classical monocytes are the major precursors of rat osteoclasts

To dissect which subset of bone marrow monocyte is the major precursor of osteoclast,3-month-old rat bone marrow was obtained for single-cell RNA sequencing.A total of 6091 cells were acquired for detailed analysis,with a median number of 1206 genes detected per cell and 17,959 genes detected in total.A total of 19 cell clusters were recognized,with the main lineages identified as B cells,Granulocytes,Monocytes,T cells,Erythrocytes and Macrophages.Monocytes were further divided into classical monocytes and non-classical monocytes.Compared with non-classical monocytes,classical monocytes highly expressed osteoclast differentiation related genes Mitf,Spi1,Fos and Csf1r.Additionally,biological processes of classical monocytes were related to osteoclast differentiation.qPCR revealed differentially expressed genes of classical monocytes played a role in osteoclast differentiation.In conclusion,classical monocytes were identified as the main precursors of osteoclasts in rats,and may contribute to osteoclast differentiation by regulating S100a4,S100a6,S100a10,Fn1,Vcan and Bcl2a1.The results of this study contribute to the understanding of the origin of osteoclasts and may provide potential biomarkers for early diagnosis of bone metabolic diseases,as well as molecular and cellular targets for clinical intervention in bone metabolic diseases.

Cyclic biaxial tensile strain enhances osteogenic differentiation in rat bone marrow-derived mesenchymal stem cells via activating ERα-Wnt3a/β-catenin pathway

The present study was designed to investigate the role of estrogen receptorα(ERα)in biaxial tensile strain(BTS)regulated osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells(rBMSCs).rBMSCs were derived fromrats and overexpressed ERα.The rBMSCs were subjected to BTS at 1Hz with a strain of 2%for 4 h per day,3 days,with or without ERαinhibitor ICI 182,780(ICI).Then,bone mineralization was performed by Alizarin Red Staining.The markers of osteogenic differentiation and downstream Wnt3a/β-catenin signaling were detected by western blotting.Results showed that BTS enhanced the osteogenic differentiation of rBMSCs,increased protein expression levels of alkaline phosphatase(ALP),runt-related transcription factor 2(Runx2),collagen type I(Col I)and osteocalcin(OCN),and it increased the protein expression levels of estrogen receptor(ER)α(ERα),Wnt3a,andβ-catenin.BTS The activated Wnt3a/β-catenin signaling pathway induced by BTS was abolished by ICI 182,780(ICI).In addition,overexpressing ERαin rBMSCs promoted the osteogenic differentiation by BTS.Taken together,BTS induced osteogenic differentiation of rBMSCs via the ERαand downstream canonical Wnt3a/β-catenin pathway.