CircHIPK3 prevents chondrocyte apoptosis and cartilage degradation by sponging miR‐30a‐3p and promoting PON2

Osteoarthritis (OA) is a common joint disease featured by the deterioration of articular cartilage and chondrocyte death. Emerging evidence has indicated that circular RNAs (circRNAs) play an essential role in OA progress. Here, we found that the expression of circHIPK3 was significantly decreased in human and mouse OA cartilage. Knocking down circHIPK3 increased apoptosis and intracellular ROS level in HC‐a chondrocytes. We performed proteomic studies and identified that circHIPK3 regulated chondrocyte apoptosis through the mitochondrial pathway. Results of JC‐1 staining and western blot further confirmed that mitochondrial outer membrane permeabilization was promoted in HC‐a chondrocytes transfected by circHIPK3 siRNA. In terms of mechanism, we showed that PON2 functioned as a potential target of circHIPK3 to regulate chondrocyte apoptosis. Moreover, we revealed that circHIPK3 interacted with miR‐30a‐3p to regulate PON2 expression in chondrocytes. Taken together, our findings suggested that circHIPK3 regulated chondrocyte apoptosis by mitochondrial pathway, and targeting the circHIPK3/miR‐30a‐3p/PON2 axis might be a potential strategy for OA treatment.

The current study revealed the important role of circHIPK3 in regulating chondrocyte apoptosis and maintaining extracellular matrix (ECM) homeostasis. Mechanistically, circHIIPK3 might serve as a sponge of miR‐30a‐3p to regulate PON2 expression. The downregulation of circHIIPK3 resulted in the increased expression of miR‐30a‐3p and decreased expression of PON2, thus leading to mitochondrial pathway apoptosis and ECM destruction.     

TGF‐β induces SOX2 expression in a time‐dependent manner in human melanoma cells

The sry‐related high‐mobility box (SOX)‐2 protein has recently been proven to play a significant role in progression, metastasis, and clinical prognosis spanning several cancer types. Research on the role of SOX2 in melanoma is limited and currently little is known about the mechanistic function of this gene in this context. Here, we observed high expression of SOX2 in both human melanoma cell lines and primary melanomas in contrast to melanocytic nevi. This overexpression in melanoma can, in part, be explained by extra gene copy numbers of SOX2 in primary samples. Interestingly, we were able to induce SOX2 expression, mediated by SOX4, via TGF‐β1 stimulation in a time‐dependent manner. Moreover, the knockdown of SOX2 impaired TGF‐β‐induced invasiveness. This phenotype switch can be explained by SOX2‐mediated cross talk between TGF‐β and non‐canonical Wnt signaling. Thus, we propose that SOX2 is involved in the critical TGF‐β signaling pathway, which has been shown to correlate with melanoma aggressiveness and metastasis. In conclusion, we have identified a novel downstream factor of TGF‐β signaling in melanoma, which may have further implications in the clinic.     

Comprehensive Analysis of Synonymous Codon Usage Bias for Complete Genomes and E2 Gene of Atypical Porcine Pestivirus

Atypical porcine pestivirus (APPV) is an emerging novel pestivirus causing the congenital tremor (CT) in piglets. The worldwide distribution characteristic of APPV make it a threat to global swine health. E2 is the major envelope glycoprotein of APPV and the crucial target for vaccine development. Considering the genetic variability of APPV complete genomes and its E2 gene as well as gaps for codon analysis, a comprehensive analysis of codon usage patterns was performed. Relative synonymous codon usage (RSCU) and effective number of codon (ENC) analyses showed that a relatively instable change existed and a slight low codon usage bias (CUB) were displayed in APPV genomes. ENC-plot analysis and correlation analyses of nucleotide compositions and ENC showed that mutation pressure and natural selection both affected the codon usage bias of the APPV and natural selection had a more obvious influence for E2 gene compared with complete genomes. Principal component analysis (PCA) and correlation analyses confirmed the above results. Correlation analyses between Gravy and Aromaticity values and the codon bias showed that natural selection played an important role in shaping the synonymous codon bias. Furthermore, neutrality plot analysis showed that natural selection was the main force while mutation pressure was a minor force influencing the codon usage pattern of the APPV E2 gene and complete genomes. The results could illustrate the codon usage patterns of APPV genomes and provided valuable basic data for further fundamental research of evolution of APPV.

     

Astragaloside IV Attenuates Glutamate-Induced Neurotoxicity in PC12 Cells through Raf-MEK-ERK Pathway

Astragaloside IV (AGS-IV) is a main active ingredient of Astragalus membranaceus Bunge, a medicinal herb prescribed as an immunostimulant, hepatoprotective, antiperspirant, a diuretic or a tonic as documented in Chinese Materia Medica. In the present study, we employed a high-throughput comparative proteomic approach based on 2D-nano-LC-MS/MS to investigate the possible mechanism of action involved in the neuroprotective effect of AGS-IV against glutamate-induced neurotoxicity in PC12 cells. Differential proteins were identified, among which 13 proteins survived the stringent filter criteria and were further included for functional discussion. Two proteins (vimentin and Gap43) were randomly selected, and their expression levels were further confirmed by western blots analysis. The results matched well with those of proteomics. Furthermore, network analysis of protein-protein interactions (PPI) and pathways enrichment with AGS-IV associated proteins were carried out to illustrate its underlying molecular mechanism. Proteins associated with signal transduction, immune system, signaling molecules and interaction, and energy metabolism play important roles in neuroprotective effect of AGS-IV and Raf-MEK-ERK pathway was involved in the neuroprotective effect of AGS-IV against glutamate-induced neurotoxicity in PC12 cells. This study demonstrates that comparative proteomics based on shotgun approach is a valuable tool for molecular mechanism studies, since it allows the simultaneously evaluate the global proteins alterations.     

基于Lake模型的Pb胁迫对木荷和栾树幼树叶片叶绿素荧光参数的影响研究

以阔叶树种木荷和栾树1年生幼树为对象,采用室内盆栽,通过配制3个不同浓度梯度的Pb Cl_2溶液于盆栽土壤中(L1L2L3),对比研究Pb胁迫下两种幼树叶片叶绿素荧光参数的响应规律,运用Lake模型从能量平衡及分配的角度揭示不同浓度Pb胁迫下木荷和栾树光系统Ⅱ运转状况,并为木本植物幼树耐Pb程度的快速诊断提供数据支撑。结果表明:3个不同浓度的Pb处理下,两种供试幼树随着入射光强(PAR)的增大,除非调节性能量耗散(Y_(NO))以外其他叶绿素荧光参数均随着PAR的变化而变化,相对电子传递速率(r ETR)和可调节性能量耗散(Y_(NPQ))呈上升趋势,而光系统Ⅱ(PSⅡ)量子效率(Y_(Ⅱ))和光化学猝灭(q L)呈下降趋势。同时,两种供试幼树的最大光能利用效率(Fv/Fm)、r ETR、Y_(Ⅱ)、q L,随着Pb污染浓度的增加而降低,而Y_(NPQ)和Y_(NO)则随着Pb污染浓度的增加而升高。Pb对两种供试植物叶绿素荧光参数的抑制效果在最大净光合速率(Pn)上也有体现。本实验还得出,在L1浓度时木荷PSⅡ反应中心的开放程度能保持在较高水准,随着污染浓度的增大,其光能转化能力弱于栾树。同时,栾树调节能量耗散的能力和对Pb胁迫的敏感程度均高于木荷,进一步说明了栾树对Pb的耐性高于木荷。综合分析后得出,Y_(NO)和Y_(NPQ)可作为植物Pb胁迫的评价指标。     

长白山区天桥岭野生杓兰属植物的多样性研究

兰科植物对生境的要求较高,温带地区分布的兰科植物非常有限。利用实地定点观察,样方设置等方法对长白山区进行杓兰属植物的物种、生境及物候进行调查分析。结果表明长白山区天桥岭长2 km,宽1 km,海拔300～500 m的山沟内集中分布着4种杓兰属植物,其中杓兰组物种均具有较高的花色多样性,杓兰属植物的开花期集中在6月4～13日。     

Genome-wide analysis and expression profiling of PP2C clade D under saline and alkali stresses in wild soybean and <Emphasis Type="Italic">Arabidopsis</Emphasis>

Protein phosphatase 2Cs (PP2Cs) belong to the largest protein phosphatase family in plants. Some members have been described as being negative modulators of plant growth and development, as well as responses to hormones and environmental stimuli. However, little is known about the members of PP2C clade D, which may be involved in the regulation of signaling pathways, especially in response to saline and alkali stresses. Here, we identified 13 PP2C orthologs from the wild soybean (Glycine soja) genome. We examined the sequence characteristics, chromosome locations and duplications, gene structures, and promoter cis-elements of the PP2C clade D genes in Arabidopsis and wild soybean. Our results showed that GsPP2C clade D (GsAPD) genes exhibit more gene duplications than AtPP2C clade D genes. Plant hormone and abiotic stress-responsive elements were identified in the promoter regions of most PP2C genes. Moreover, we investigated their expression patterns in roots, stems, and leaves. Quantitative real-time PCR analyses revealed that the expression levels of representative GsPP2C and AtPP2C clade D genes were significantly influenced by alkali and salt stresses, suggesting that these genes might be associated with or directly involved in the relevant stress signaling pathways. Our results established a foundation for further functional characterization of PP2C clade D genes in the future.     

Auricular Vagus Nerve Stimulation Exerts Antiinflammatory Effects and Immune Regulatory Function in a 6-OHDA Model of Parkinson’s Disease

According to epidemiologic studies, smoking appears to downregulate the prevalence of Parkinson’s disease (PD), possibly due to antiinflammatory mechanisms via activation of α7 nicotinic acetylcholine receptors (α7 nAChRs). This receptor also appears to play a role in T-cell differentiation. Recently, it has become apparent that the innate immune system participates in PD pathogenesis. The aim of this study was to evaluate the effects of auricular vagus nerve stimulation (aVNS) on substantia nigra (SN) dopaminergic neurodegeneration and the associated neuroinflammation and immune responses in a rat PD model. Adult male Wistar rats were unilaterally administered 6-hydroxydopamine (6-OHDA) to the medial forebrain bundle, followed by aVNS treatment after surgery. Following motor behavioral tests, the expression of tyrosine hydroxylase (TH) in the SN and the levels of inflammatory cytokines in the ventral midbrain were evaluated. In addition, changes in the trends of subsets of CD4+ T lymphocytes in the SN were measured by immunofluorescence staining. Western blotting was used to evaluate the α7 nAChR protein level. Compared with 6-OHDA treats rats, aVNS treatment significantly improved motor deficits, increased TH and α7 nAChR expression, and reduced the levels of inflammatory cytokines (tumor necrosis factor-a (TNF-α) and interleukin-1β (IL-1β)) (p?<?0.05). Additionally, aVNS increased the numbers of regulatory T (Treg) cells while decreasing T helper (Th)17 cells. aVNS exerted neuroprotective effects against dopaminergic damage, possibly by suppressing the evolution of inflammation and modulating innate immune responses. Thus, aVNS may be a potential promising therapy in the future.