Characterization of the sphingolipid profiling of Emiliania huxleyi against virus infection

Lipidomics approach by UPLC-Q-Exactive-MS was used for the identification,quantification,comparison,and characterization of sphingolipids in virus infected marine Emiliania huxleyi BOF92 cells.The results show that 16 significantly changed sphingolipids(including Cer,CerG1,and SPHm)were identified during viral infection.Our data confirmed previously recognized facts that viral infection led to a shift toward virus-specific sphingolipids,which is consistent with the down-regulation of genes involved in the host de novo sphingolipid biosynthesis.Moreover,we revealed the upregulation of virusencoded homologous genes participating in de novo sphingolipids biosynthesis and virus-specific hydroxylated long chain bases(LCBs)as phytoCer,suggesting the competitive inhibition of host sphingolipid synthesis to produce the required building blocks for viral production,replication,and assembly.Additionally,Cer 40꞉1;2,Cer 40꞉2;2 isomer,and CerG139꞉0;2,Cer 39꞉0;2 as novel metabolite markers might indicate the general dysfunctions in E.huxleyi in response to viral infection.Our results show that viral infection led to a profound remodeling of host sphingolipidome,by which viruses depend on the hijacking of host sphingolipid metabolism to support the viral life cycle.

Pollination Biology of the Endangered Herbal Medicines Dendrobium chrysotoxum(Orchidaceae)

Pollination biology studies of the endangered herbal medicines Dendrobium chrysotoxum were conducted in natural pollination conditions using flower observation,pollinator observation and artificial pollination experiments.Populations of D.chrysotoxum with fragrance and nectar were pollinated by Ctenoplectra davidi Valhalla(Hymenoptera:Apidae)species.The floral structure of D.chrysotoxum adapted precisely to its pollinators.Flowers had a low capsule setting(0.17%)under natural conditions.However,compared to open pollination,artificial pollination experiments showed a significant increase in capsule setting,and D.chrysotoxum was cross-compatible and self-compatible,but there was pollinator limitation also.This study will provide important information for the preservation of this endangered species.

赫氏颗石藻(Emiliania huxleyi)响应病毒感染的microRNA转录组分析

海洋颗石藻病毒–宿主互作是影响海洋碳、硫生物地化循环及全球气候变化的重要环节。作为大的双链DNA病毒,颗石藻病毒进化出一种“病毒细胞代谢”模式,通过重编程宿主代谢途径以满足其代谢需求,但对这一代谢模式的调控机制尚缺乏足够的认识。MicroRNA(miRNA)作为一种基因表达调控的重要因子,能够通过调控代谢过程中的靶基因表达,从而调节相关代谢通路。本研究采用small RNA测序技术分析病毒感染颗石藻差异表达的miRNA及其靶基因功能,鉴定出26条成熟miRNA(包括2条病毒来源的miRNA),均来自23条新的miRNA前体序列,其中5条miRNA显著差异表达,包括4条上调,1条下调。实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)验证结果与miRNA-seq结果基本一致。功能富集分析显示,5个差异表达的miRNA可能参与调节糖代谢、脂代谢和氨基酸等代谢。此外,差异表达miRNA的表达水平与脂质代谢相关靶基因如ACC-1、SPT、ACOX、ACAT、CERS、ACADS等的表达水平呈负相关,说明这些miRNA可能在病毒感染过程中对宿主的脂质代谢发挥重要的调控作用。

Transformation of coccolithophorid Emiliania huxleyi harboring a marine virus(Coccolithoviruses)serine palmitoyltransferase(SPT)gene by electroporation

Emiliania huxleyi is the most prominent modern coccolithophore,a group of marine unicellular eukaryotes that play a critical role in ocean biogeochemistry.Coccolithoviruses are large double stranded DNA viruses,which is responsible for the demise of large oceanic blooms formed by E.huxleyi.E.huxleyi virus(EhVs)acquired a series of enzyme-coding genes predicted to be involved in the sphingolipid biosynthesis by horizontal gene transfer between virus-host.Currently,there is limited experimental validation identifying the functions of these genes in EhV.Genetic transformation of eukaryotic cells is a powerful tool to get an insight into gene functions of the studied organisms.Serine palmitoyltransferase(SPT)catalyzes the first committed step in de novo sphingolipid biosynthetic pathway.Here,a novel vector system for the transformation of E.huxleyi was designed.It contained fragments of promoter and terminator sequences of E.huxleyi endogenic fucoxanthin chlorophyll a/c-binding protein gene“fcp”and harbored EhV-99B1 spt gene.The resultant recombinant transformation vectors pEhux-I-spt and pEhux-II were co-transferred into E.huxleyi BOF92 by electroporation.Transformants were obtained upon glufosinate-ammonium selection,and confirmed by Southern hybridization,genome PCR,qRT-PCR and Western blot screening of spt gene,which indicated that spt gene was integrated into the nuclear genome and was expressed at the mRNA and protein levels.The expression of the viral spt gene led to differences in lipid compositions analyzed using thin-layer chromatography(TLC).The results present the genetic transformation system for E.huxleyi,providing additional genetic resource with potential for exploring basic biological questions such as the virus-host interactions.

Fetuin-A is an immunomodulator and a potential therapeutic option in BMP4-dependent heterotopic ossification and associated bone mass loss

Heterotopic ossification(HO)is the abnormal formation of bone in extraskeletal sites.However,the mechanisms linking HO pathogenesis with bone mass dysfunction remain unclear.Here,we showed that mice harboring injury-induced and BMP4-dependent HO exhibit bone mass loss similar to that presented by patients with HO.Moreover,we found that injury-induced hyperinflammatory responses at the injury site triggered HO initiation but did not result in bone mass loss at 1 day post-injury(dpi).In contrast,a suppressive immune response promoted HO propagation and bone mass loss by 7 dpi.Correcting immune dysregulation by PD1/PDL1 blockade dramatically alleviated HO propagation and bone mass loss.We further demonstrated that fetuin-A(FetA),which has been frequently detected in HO lesions but rarely observed in HO-adjacent normal bone,acts as an immunomodulator to promote PD1 expression and M2 macrophage polarization,leading to immunosuppression.Intervention with recombinant FetA inhibited hyperinflammation and prevented HO and associated bone mass loss.Collectively,our findings provide new insights into the osteoimmunological interactions that occur during HO formation and suggest that FetA is an immunosuppressor and a potential therapeutic option for the treatment of HO.

Expression and significance of NRP-1 in xenografts of lung cancer cell in nude mouse

Objective: To establish angiogenesis model of xenografts of lung cancer cell in nude mouse and investigate the expression of the neuropilin-1 (NRP-1) protein in tumors and its role in progression and angiogenesis of lung cancer. Methods: Human lung adenocarcinoma cells A549 were analyzed for the expression of vascular endothelial growth factor- 165 (VEGF165) mRNA using RT-PCR in vitro. Two groups of nude mice were subcutaneously inoculated with A549 at differ- ent tumor-loading time. Two groups of xenografts were identified by hematoxylin and eosin (HE) staining, their microvessel density (MVD) were analyzed meanwhile. Two groups were analyzed for the expression of NRP-1 protein and their mean absorbency by using immunohistochemistry and automatic image analysis system respectively. Results: A549 expressed VEGF165 mRNA, and xenografts of A549 in nude mice were successfully established and confirmed by HE staining. The atypia of cancer cells and angiogenesis were occurred in two groups. Two groups of MVD were 13.06 ± 1.58, 23.61 ± 3.11 (ves- sels/mm2) (P < 0.01). NRP-1 protein was expressed in cytoplasm of vascular endothelium cells and partial tumor cells. Two groups of mean absorbency of NRP-1 were 0.1095 ± 0.0228, 0.1784 ± 0.0151 (P < 0.01). Conclusion: The angiogenesis models of xenografts in nude mice with lung cancer cell A549 expressing VEGF165 mRNA at different tumor-loading times were established successfully. The expression of NRP-1 protein and MVD were increased with the tumor progression. Our results demonstrate that NRP-1 protein in lung cancer is related to angiogenesis.

PD-1/PD-L1 blockade in cervical cancer: current studies and perspectives

Cervical cancer (CC) is the fourth most commonly diagnosed female malignancy and a leading cause of cancer-related mortality worldwide, especially in developing countries. Despite the use of advanced screening and preventive vaccines, more than half of all CC cases are diagnosed at advanced stages, when therapeutic options are extremely limited and side effects are severe. Given these circumstances, new and effective treatments are needed. In recent years, exciting progress has been made in immunotherapies, including the rapid development of immune checkpoint inhibitors. Checkpoint blockades targeting the PD-1/PD-L1 axis have achieved effective clinical responses with acceptable toxicity by suppressing tumor progression and improving survival in several tumor types. In this review, we summarize recent advances in our understanding of the PD-1/PD-L1 signaling pathway, including the expression patterns of PD-1/PD-L1 and potential PD-l/PD-Ll-related therapeutic strategies for CC.