Intramyocardial transplantation of cardiac telocytes decreases myocardial infarction and improves post‐infarcted cardiac function in rats

The midterm effects of cardiac telocytes (CTs) transplantation on myocardial infarction (MI) and the cellular mechanisms involved in the beneficial effects of CTs transplantation are not understood. In the present study, we have revealed that transplantation of CTs was able to significantly decrease the infarct size and improved cardiac function 14 weeks after MI. It has established that CT transplantation exerted a protective effect on the myocardium and this was maintained for at least 14 weeks. The cellular mechanism behind this beneficial effect on MI was partially attributed to increased cardiac angiogenesis, improved reconstruction of the CT network and decreased myocardial fibrosis. These combined effects decreased the infarct size, improved the reconstruction of the LV and enhanced myocardial function in MI. Our findings suggest that CTs could be considered as a potential cell source for therapeutic use to improve cardiac repair and function following MI, used either alone or in tandem with stem cells.     

Insights into the structural nature of the transition state in the Kir channel gating pathway

In a previous study we identified an extensive gating network within the inwardly rectifying Kir1.1 (ROMK) channel by combining systematic scanning mutagenesis and functional analysis with structural models of the channel in the closed, pre-open and open states. This extensive network appeared to stabilize the open and pre-open states, but the network fragmented upon channel closure. In this study we have analyzed the gating kinetics of different mutations within key parts of this gating network. These results suggest that the structure of the transition state (TS), which connects the pre-open and closed states of the channel, more closely resembles the structure of the pre-open state. Furthermore, the G-loop, which occurs at the center of this extensive gating network, appears to become unstructured in the TS because mutations within this region have a ‘catalytic’ effect upon the channel gating kinetics.     

干旱胁迫下外源水杨酸对黄瓜幼苗膜脂过氧化和光合特性的影响

为了探讨外源水杨酸(SA)提高植物抗旱性的相关机制,研究了干旱胁迫下(基质含水量为饱和持水量的60％和50％),根际施用外源SA对黄瓜幼苗生长、膜脂过氧化、脯氨酸积累、水分利用效率、净光合速率(Pn)和叶绿素荧光参数的影响.结果表明:SA处理能够缓解干旱胁迫对黄瓜幼苗生长、Pn和水分利用效率的抑制,减小膜脂过氧化程度,促进脯氨酸的积累;添加外源SA显著减小了干旱胁迫下黄瓜幼苗的PSⅡ最大光化学效率、PSⅡ实际光化学效率、PSⅡ潜在活性、PSⅡ有效光化学效率和光化学猝灭系数的下降幅度,抑制了非光化学猝灭系数的升高.添加外源SA可以缓解干旱胁迫造成的膜脂过氧化对膜系统的氧化损伤,并通过增强PSⅡ反应中心活性提高了Pn,有助于水分的利用,同时增大渗透调节能力,减少水分的散失,提高水分利用效率,从而增强植株对干旱的适应能力.     

Wogonin inhibits IGF-1-stimulated cell growth and estrogen receptor α expression in breast adenocarcinoma cell and angiogenesis of chick chorioallantoic membrane

The aim of the present study was to investigate the involvements of insulin-like growth factor-1 (IGF-1) and estrogen receptor α (ERα) in the inhibitory effect of wogonin on the breast adenocarcinoma growth. Moreover, the effect of wogonin on the angiogenesis of chick chorioallantoic membrane (CAM) was also investigated. MCF-7 cells (human breast adenocarcinoma cell line) were subjected to several drugs, including IGF-1, wogonin and ER inhibitor ICI182780, alone or in combination. MTT assay was used to detect breast cancer proliferation. Western blot was used to analyze ERα and p-Akt expression levels. CAM models prepared from 6-day chicken eggs were employed to evaluate angiogenesis inhibition. The results showed wogonin and ICI182780 both exhibited a potent ability to blunt IGF-1-stimulated MCF-7 cell growth. Either of wogonin and ICI182780 significantly inhibited ERα and p-Akt expressions in IGF-1-treated cells. The inhibitory effect of wogonin showed no difference from that of ICI182780 on IGF-1-stimulated expressions of ERα and p-Akt. Meanwhile, wogonin at different concentrations showed significant inhibitory effect on CAM angiogenesis. These results suggest the inhibitory effect of wogonin on breast adenocarcinoma growth via inhibiting IGF-1-mediated PI3K-Akt pathway and regulating ERα expression. Furthermore, wogonin has a strong anti-angiogenic effect on CAM model.     

Neurodegeneration-associated TDP-43 interacts with fragile X mental retardation protein (FMRP)/Staufen (STAU1) and regulates SIRT1 expression in neuronal cells

Despite the identification of the 43 kDa transactive response DNA-binding protein (TDP-43) as a major pathological signatory protein in a wide range of neurodegenerative diseases, the mechanistic role of TDP-43 in neurodegenerative disorders is still poorly understood. Here, we report that TDP-43 is physically associated with fragile X mental retardation protein (FMRP) and Staufen (STAU1) to form a functional complex. Differential microarray analysis revealed that the expression of a collection of functionally important genes including Sirtuin (SIRT1) is regulated by this complex. RNA-immunoprecipitation (RIP) and RNA pull-down assays demonstrated that TDP-43/FMRP/STAU1 specifically binds to the 3'-UTR of SIRT1 mRNA, and that knockdown the expression of any one of these three proteins resulted in the reduction of SIRT1 mRNA and protein. SIRT1 is implicated in double-stranded DNA break repair and is required for cell survival. Indeed, depletion of TDP-43/FMRP/STAU1 sensitizes cells to apoptosis and DNA damages. Collectively, our results revealed a molecular mechanism for the cellular function of TDP-43 and might shed new light on the understanding of the mechanistic role of TDP-43 in neurodegenerative diseases.     

Exosome-mediated mRNA delivery in vivo is safe and can be used to induce SARS-CoV-2 immunity

Functional delivery of mRNA has high clinical potential. Previous studies established that mRNAs can be delivered to cells in vitro and in vivo via RNA-loaded lipid nanoparticles (LNPs). Here we describe an alternative approach using exosomes, the only biologically normal nanovesicle. In contrast to LNPs, which elicited pronounced cellular toxicity, exosomes had no adverse effects in vitro or in vivo at any dose tested. Moreover, mRNA-loaded exosomes were characterized by efficient mRNA encapsulation (∼90%), high mRNA content, consistent size, and a polydispersity index under 0.2. Using an mRNA encoding the red light-emitting luciferase Antares2, we observed that mRNA-loaded exosomes were superior to mRNA-loaded LNPs at delivering functional mRNA into human cells in vitro. Injection of Antares2 mRNA-loaded exosomes also led to strong light emission following injection into the vitreous fluid of the eye or into the tissue of skeletal muscle in mice. Furthermore, we show that repeated injection of Antares2 mRNA-loaded exosomes drove sustained luciferase expression across six injections spanning at least 10 weeks, without evidence of signal attenuation or adverse injection site responses. Consistent with these findings, we observed that exosomes loaded with mRNAs encoding immunogenic forms of the SARS-CoV-2 Spike and Nucleocapsid proteins induced long-lasting cellular and humoral responses to both. Taken together, these results demonstrate that exosomes can be used to deliver functional mRNA to and into cells in vivo.     

几种盐肤木属植物的染色体观察

盐肤木(Rhus)属(广义)是漆树科中最多态最大的属,全世界分布有300余种,我国有20余种。本文报道了4种盐肤木属(Rhus)植物的染色体观察结果:1.盐肤木R.chinensis 2n=30,有0-5个B染色体存在;2.青麸杨R.potaninii 2n=30,本文为首次报道;3.火矩树R.typhiflua 2n=30;4.R.verniciflua 2n=30,但其中一个栽培品种为三倍体(2n=3x=45)。盐肤木、青麸杨为我国重要的倍子树,漆树是我国特种经济林木,火矩树为速生绿化风景树种,本文为进一步发掘利用及深入研究这些植物提供了细胞学依据。B染色体在木本植物中极少出现,在盐肤木中发现B染色体,对深入研究B染色体的起源、分布等有一定的意义。同时本文为Rhus属的分类问题提供了一些细胞学信息。     

The effects of three years of fencing enclosure on soil seed banks and the relationship with above-ground vegetation of degraded alpine grasslands of the Tibetan plateau

Background and Aims

Fenced enclosures have become an important method for re-establishing degraded grassland on the Tibetan plateau, and examination of soil seed banks may provide useful insights to understanding the effects and mechanisms of fencing enclosure on the restoration.

Methods

An investigation was conducted into the effects of enclosure for 3 years on the soil seed banks of degraded natural and sown grasslands at eight study sites. Species composition, soil seed bank density and the relationships with above-ground vegetation were analysed based on 4800 soil core samples and counting of seeds extracted from soil samples.

Results

After 3 years of fencing enclosure, soil seed banks differed between the different communities across the study sites. Species numbers and seed density in soil seed banks decreased from natural grassland to sown grassland, with most seeds occurring in the upper 5 cm soil layer. In these alpine grasslands, relatively few species produced high numbers of seeds, although their occurrence across the eight study sites was variable. Total vegetation cover increased with enclosure due to the colonization capacity of the vegetation rather than soil seed banks.

Conclusions

This study provided evidence that soil seed banks do not play an important role in the restoration of degraded alpine grassland when using fencing enclosures. Further studies conducted over longer periods are needed to address this subject.