Regulatory mechanisms of iron homeostasis in maize mediated by ZmFIT

Regulation of iron homeostasis in maize remains unclear,despite the known roles of FER-Like Fe deficiency-induced transcription factor(FIT)in Arabidopsis and rice.ZmFIT,like At FIT and Os FIT,interacts with iron-related transcription factors 2(ZmIRO2).Here,we investigate the involvement of ZmFIT in iron homeostasis.Mutant ZmFIT lines exhibiting symptoms of Fe deficiency had reduced shoot iron content.Transcriptome analysis revealed downregulation of Fe deficiency-responsive genes in the roots of a Zmfit mutant.ZmFIT facilitates the nuclear translocation of ZmIRO2 to activate transcription of downstream genes under Fe-deficient conditions.Our findings suggest that ZmFIT,by interaction with ZmIRO2,mediates iron homeostasis in maize.Notably,the binding and activation mechanisms of ZmFIT resemble those in Arabidopsis but differ from those in rice,whereas downstream genes regulated by ZmFIT show similarities to rice but differences from Arabidopsis.In brief,ZmFIT,orthgologs of Os FIT and At FIT in rice and maize,respectively,regulates iron uptake and homeostasis in maize,but with variations.

Neuron-to-astrocyte proteostatic stress signaling in response to tau pathology

Maintenance of protein homeostasis or“proteostasis”is essential for the functioning and viability of cells.This is in particular the case for cells like neurons that cannot self-renew and acquire unique functional properties during their lifetime.Cellular proteostatic stress responses are in place to protect cells from damage in case of proteostatic challenges.The integrated stress response(ISR)is one of the key proteostatic stress responses in the cell(Costa-Mattioli and Walter,2020).The ISR is the downstream convergence point for the four stress-induced eIF2αkinases(EIF2AK1-4)that control stress-regulated protein translation via phosphorylation of the translation factor eIF2α.ISR activation results in a transient reduction of global translation while it concomitantly enhances the translation of specific mRNAs,including that encoding the activating transcription factor 4(ATF4).Together,the translational control mediated by the ISR results in a temporary reduction of the overall protein load and the selectively increased expression of proteins that contribute to restoration of the proteostatic balance.

Sox2 transcription network acts as a molecular switch to regulate properties of neural stem cells

Neural stem cells(NSCs) contribute to ontogeny by producing neurons at the appropriate time and location. Neurogenesis from NSCs is also involved in various biological functions in adults. Thus, NSCs continue to exert their effects throughout the lifespan of the organism. The mechanism regulating the core functional properties of NSCs is governed by intra- and extracellular signals. Among the transcription factors that serve as molecular switches, Sox2 is considered a key factor in NSCs. Sox2 forms a core network with partner factors, thereby functioning as a molecular switch. This review discusses how the network of Sox2 partner and target genes illustrates the molecular characteristics of the mechanism underlying the self-renewal and multipotency of NSCs.

Extracellular matrix remodelling in dental pulp tissue of carious human teeth through the prism of single-cell RNA sequencing

Carious lesions are bacteria-caused destructions of the mineralised dental tissues,marked by the simultaneous activation of immune responses and regenerative events within the soft dental pulp tissue.While major molecular players in tooth decay have been uncovered during the past years,a detailed map of the molecular and cellular landscape of the diseased pulp is still missing.In this study we used single-cell RNA sequencing analysis,supplemented with immunostaining,to generate a comprehensive single-cell atlas of the pulp of carious human teeth.Our data demonstrated modifications in the various cell clusters within the pulp of carious teeth,such as immune cells,mesenchymal stem cells(MSC)and fibroblasts,when compared to the pulp of healthy human teeth.Active immune response in the carious pulp tissue is accompanied by specific changes in the fibroblast and MSC clusters.These changes include the upregulation of genes encoding extracellular matrix(ECM)components,including COL1A1 and Fibronectin(FN1),and the enrichment of the fibroblast cluster with myofibroblasts.The incremental changes in the ECM composition of carious pulp tissues were further confirmed by immunostaining analyses.Assessment of the Fibronectin fibres under mechanical strain conditions showed a significant tension reduction in carious pulp tissues,compared to the healthy ones.The present data demonstrate molecular,cellular and biomechanical alterations in the pulp of human carious teeth,indicative of extensive ECM remodelling,reminiscent of fibrosis observed in other organs.This comprehensive atlas of carious human teeth can facilitate future studies of dental pathologies and enable comparative analyses across diseased organs.

Structure and Expression of Several Putative Cdc42-Interacting Proteins in Magnaporthe grisea

MgCdc42 （Cdc42 in Magnaporthe grisea）, with high homology to ScCdc42 （Cdc42 in Saccharomyces cerevisiae）, has been demonstrated to involve in the morphogenesis and infection process. To further understand the signaling network, the putative MgCdc42-interacting proteins were analyzed. ScCdc42-interacting protein sequences were first used to BLAST against the M. grisea genome database to retrieve their corresponding analogs. Subsequently, conserved domains of these proteins were compared and expression patterns of their encoding genes in different MgCdc42 mutation states were analyzed by semiquantitative RT-PCR. All retrieved analogs of ScCdc42-interacting proteins from the M. grisea database have conserved domains as those in S. cerevisiae. Expression of their encoding genes increased in MgCdc42CA mutant and decreased in MgCdc42KO mutant. However, MgBeml, Chin1, and MgGicl in MgCdc42DN mutant had the same expression level as that in the wild type, although MgBem4, MgBoi2, MgCdc24, MgGic2, MgRgal, and Mst20 had decreased expression level, as expected. Overall, it is concluded that there may exist a similar Cdc42 signal pathway in M. grisea as in S. cerevisiae and MgCdc42 plays a key role in the pathway.

Self-assembled multifunctional DNA nanoflowers for the circumvention of multidrug resistance in targeted anticancer drug delivery

Cancer chemotherapy has been limited by its side effects and multidrug resistance （MDR）, the latter of which is partially caused by drug efflux from cancer cells. Thus, targeted drug delivery systems that can circumvent MDR are needed. Here, we report multifunctional DNA nanoflowers （NFs） for targeted drug delivery to both chemosensitive and MDR cancer cells that circumvented MDR in both leukemia and breast cancer cell models. NFs are self-assembled via potential co-precipitation of DNA and magnesium pyrophosphate generated by rolling circle replication, during which NFs are incorporated using aptamers for specific cancer cell recognition, fluorophores for bioimaging, and doxorubicin （Dox）- binding DNA for drug delivery. NF sizes are tunable （down to N200 nm in diameter）, and the densely packed drug-binding motifs and porous intrastructures endow NFs with a high drug-loading capacity （71.4%, wt/wt）. Although the Dox- loaded NFs （NF-Dox） are stable at physiological pH, drug release is facilitated under acidic or basic conditions. NFs deliver Dox into target chemosensitive and MDR cancer cells, preventing drug efflux and enhancing drug retention in MDR cells. NF-Dox induces potent cytotoxicity in both target chemosensitive cells and MDR cells, but not in nontarget cells, thus concurrently circumventing MDR and reducing side effects. Overall, these NFs are promising tools for circumventing MDR in targeted cancer therapy.

Engagement of sialylated glycans with Siglec receptors on suppressive myeloid cells inhibits anticancer immunity via CCL2

The overexpression of sialic acids on glycans,called hypersialylation,is a common alteration found in cancer cells.Sialylated glycans can enhance immune evasion by interacting with sialic acid-binding immunoglobulin-like lectin(Siglec)receptors on tumorinfiltrating immune cells.Here,we investigated the effect of sialylated glycans and their interaction with Siglec receptors on myeloid-derived suppressor cells(MDSCs).We found that MDSCs derived from the blood of lung cancer patients and tumor-bearing mice strongly express inhibitory Siglec receptors and are highly sialylated.In murine cancer models of emergency myelopoiesis,Siglec-E knockout in myeloid cells resulted in prolonged survival and increased tumor infiltration of activated T cells.Targeting suppressive myeloid cells by blocking Siglec receptors or desialylation strongly reduced their suppressive potential.We further identified CCL2 as a mediator involved in T-cell suppression upon interaction between sialoglycans and Siglec receptors on MDSCs.Our results demonstrated that sialylated glycans inhibit anticancer immunity by modulating CCL2 expression.

Gold nanorod-photosensitizer conjugate with extracellular pH-driven tumor targeting ability for photothermal/photodynamic therapy

Chlorin e6-pHLIPss-AuNRs, a gold nanorod-photosensitizer conjugate containing a pH （low） insertion peptide （pHLIP） with a disulfide bond which imparts extracellular pH （pHe）-driven tumor targeting ability, has been successfully developed for bimodal photodynamic and photothermal therapy. In this bimodal therapy, chlorin e6 （Ce6）, a second-generation photosensitizer （PS）, is used for photodynamic therapy （PDT）. Gold nanorods （AuNRs） are used as a hyperthermia agent for photothermal therapy （PTT） and also as a nanocarrier and quencher of Ce6. pHLIPss is designed as a pile-driven targeting probe to enhance accumulation of Ce6 and AuNRs in cancer cells at low pH. In Ce6- pHLIPss-AuNRs, Ce6 is close to and quenched by AuNRs, causing little PDT effect. When exposed to normal physiological pH 7.4, Ce6-pHLIPs^-AuNRs loosely associate with the cell membrane. However, once exposed to acidic pH 6.2, pHLIP actively inserts into the cell membrane, and the conjugates are translocated into cells. When this occurs, Ce6 separates from the AuNRs as a result of disulfide bond cleavage caused by intracellular glutathione （GSH）, and singlet oxygen is produced for PDT upon light irradiation. In addition, as individual PTT agent, AuNRs can enhance the accumulation of PSs in the tumor by the enhanced permeation and retention （EPR） effect. Therefore, as indicated by our data, when exposed to acidic pH, Ce6-pHLIPss-AuNRs can achieve synergistic PTT/PDT bimodality for cancer treatment.

Proteomic and metabolomic profiling underlines the stage- and time-dependent effects of high temperature on grape berry metabolism

Climate change scenarios predict an increase in mean air temperatures and in the frequency,intensity,and length of extreme temperature events in many wine-growing regions worldwide.Because elevated temperature has detrimental effects on berry growth and composition,it threatens the economic and environmental sustainability of wine production.Using Cabernet Sauvignon fruit-bearing cuttings,we investigated the effects of high temperature(HT)on grapevine berries through a label-free shotgun proteomic analysis coupled to a complementary metabolomic study.Among the 2,279 proteins identified,592 differentially abundant proteins were found in berries exposed to HT.The gene ontology categories“stress,”“protein,”“secondary metabolism,”and“cell wall”were predominantly altered under HT.High temperatures strongly impaired carbohydrate and energy metabolism,and the effects depended on the stage of development and duration of treatment.Transcript amounts correlated poorly with protein expression levels in HT berries,highlighting the value of proteomic studies in the context of heat stress.Furthermore,this work reveals that HT alters key proteins driving berry development and ripening.Finally,we provide a list of differentially abundant proteins that can be considered as potential markers for developing or selecting grape varieties that are better adapted to warmer climates or extreme heat waves.

ZmGRAS11,transactivated by Opaque2,positively regulates kernel size in maize

Although the genetic basis for endosperm development in maize(Zea mays)has been well studied,the mechanism for coordinating grain filling with increasing kernel size remains elusive.Here,we report that increased kernel size was selected during modern breeding and identify a novel DELLA-like transcriptional regulator,ZmGRAS11,which positively regulates kernel size and kernel weight in maize.We find that Opaque2,a core transcription factor for zein protein and starch accumulation,transactivates the expression of Zm GRAS11.Our data suggest that the Opaque2-Zm GRAS11 module mediates synergistic endosperm enlargement with grain filling.

Zinc-substituted hemoglobin with specific drug binding sites and fatty acid resistance ability for enhanced photodynamic therapy

Precisely designed protein-based nanodrugs, as a kind of colloidal drug system, have attracted significant attention in tumor therapy because of their refined drug loading ratio, controlled delivery efficacy and natural biocompatibility. However, most drugs are conjugated to the protein carriers randomly without specific binding sites. Moreover, such sites could easily be replaced by lipophilic molecules in the physiological environment and result in low delivery efficiency. With strong and specific binding locations especially comparatively narrow spatial binding sites and nonflexible structure, hemin (FePPIX)-free hemoglobin or apohemoglobin (apoHb), as a natural metalloporphyrin protein carrier, represents great potential in bioapplication. Therefore, we herein introduce a folate acid (FA) modified, zinc-substituted hemoglobin (ZnPHb-FA) as a naturally occurring protein matrix-based photosensitizer for cancer photodynamic therapy (PDT). Noncovalent inserted ZnPPIX molecules in apoHb possess an extremely stable property and significant recovered photoproperties with superior biocompatibility and phototoxicity, both in vitro and in vivo. This stability was verified by molecular docking analysis and calculation of binding constant, representing a total of five drug binding sites of apoHb for ZnPPIX molecules, four of which are energetically favorable (△G value of -11.9 kcal/mol), and one which is energetically acceptable (△G value of -9 kcal/mol). Folate acid modification has been shown to efficiently enhance the internalization and retention time of ZnPHb nanodrug. ZnPHb-FA is also an efficient depressor of hemin oxygenase-1 (HO-1), which could, in turn, lower the antioxidant ability of cancer cells by decreasing the production of biiirublin. Results in vitro and in vivo both indicated that the firmly combination of apoHb and ZnPPIX described here represents a novel and efficient protein nanodrug systems for cancer therapy.

Beyond Mendelian Inheritance:Genetic Buffering and Phenotype Variability

Understanding the way genes work amongst individuals and across generations to shape form and function is a common theme for many genetic studies.The recent advances in genetics,genome engineering and DNA sequencing reinforced the notion that genes are not the only players that determine a phenotype.Due to physiological or pathological fluctuations in gene expression,even genetically identical cells can behave and manifest different phenotypes under the same conditions.Here,we discuss mechanisms that can influence or even disrupt the axis between genotype and phenotype;the role of modifier genes,the general concept of genetic redundancy,genetic compensation,the recently described transcriptional adaptation,environmental stressors,and phenotypic plasticity.We furthermore highlight the usage of induced pluripotent stem cells(iPSCs),the generation of isogenic lines through genome engineering,and sequencing technologies can help extract new genetic and epigenetic mechanisms from what is hitherto considered‘noise’.

The influence of physiological environment on the targeting effect of aptamer-guided gold nanoparticles

Aptamer guided nano medicine shows great promise in targeted cancer therapies.However the loss of targeting capacity duri ng in vivo or clinical trials has largely hindered its popularity and there are no systematic studies to elucidate the causes.Herein,we investigated such loss of targeting capacity by examining how the physiological milieu affected targeting effect.Aptamer functionalized gold nanoparticle(AuNP)was chosen as the model and exposed to human blood serum that is used to mimic physiological milieu.Dynamic light scattering(DLS),flow cytometry and label-free liquid chromatography tan dem mass spectrometry(LC-MS/MS)were employed to determi ne variations of NPs'surface chemistry and biological identities changes after serum exposure.Results showed that the targeting ability loss was caused by protein corona blocking,replacement and enzymatic cleavage of surface aptamer targeting ligands.Noteworthy,the aggregation issue is critical for the smaller NPs.Analysis of the protein corona profile indicated the accumulation of immune-related proteins on the surface of aptamer-conjugated NPs,which could induce immune response,resulting in rapid clearanee of NPs.

Fabrication of ultrathin Zn（OH）2 nanosheets as drug carriers

Ultrathin two-dimensional （2D） porous Zn（OH）2 nanosheets （PNs） were fabricated by means of one-dimensional Cu nanowires as backbones. The PNs have thickness of approximately 3.8 nm and pore size of 4-10 nm. To form ＂smart＂ porous nanosheets, DNA aptamers were covalently conjugated to the surface of PNs. These ultrathin nanosheets show good biocompatibility, effident cellular uptaker and promising pH-stimulated drug release.

Identification of a novel mutation in a Chinese family with Nance-Horan syndrome by whole exome sequencing

Objective： Nance-Horan syndrome （NHS） is a rare X-linked disorder characterized by congenital nuclear cataracts, dental anomalies, and craniofacial dysmorphisms. Mental retardation was present in about 30% of the reported cases. The purpose of this study was to investigate the genetic and clinical features of NHS in a Chinese family. Methods： Whole exome sequencing analysis was performed on DNA from an affected male to scan for can- didate mutations on the X-chromosome. Sanger sequencing was used to verify these candidate mutations in the whole family. Clinical and ophthalmological examinations were performed on all members of the family. Results： A combi- nation of exome sequencing and Sanger sequencing revealed a nonsense mutation c.322G〉T （E108X）in exon 1 of NHS gene, co-segregating with the disease in the family. The nonsense mutation led to the conversion of glutamic acid to a stop codon （E108X）, resulting in truncation of the NHS protein. Multiple sequence alignments showed that codon 108, where the mutation （c.322G〉T） occurred, was located within a phylogenetically conserved region. The clinical features in all affected males and female carriers are described in detail. Conclusions： We report a nonsense mutation c.322G〉T （E108X） in a Chinese family with NHS. Our findings broaden the spectrum of NHS mutations and provide molecular insight into future NHS clinical genetic diagnosis.

Cytokine Profiling in Influenza A Virus and Staphylococcal(Co-)Infections

Influenza A virus and Staphylococcus aureus are common causative agents of pneumonia.Co-infections with these two pathogens frequently occur and are characterized,among others,by higher morbidity and mortality due to hyper-inflammation of the lungs.Here,we aimed to profile systemic and local cytokine composition at early acute stages of pneumonia in amurinemodel.Allmice recovered from single influenza A virus and/or staphylococcal infections.In contrast,co-infections led to a severe clinical outcome.While distinct cytokine patterns were detected in lungs of single-pathogen-infected animals,co-infections combined both virus-and bacteria-driven responses.However,analyses of infected human primarymonocytic cells as well as bronchial epithelial cells did not reflectmurine profiles.Based on infectious dose,mainly bacteria-driven responses were noted.The impact of single cells to cytokine composition of the lungs and translation of murine studies to humans remains uncertain and warrants further studies.

Unlocking multiplexing in deep tissue

In vivo fluorescence imaging in the second near-infrared (NIR-II)window (1000-1700 nm)has been emerging as a new powerful imaging technique and demonstrated tre- mendous potential in life sciences and biomedical applications,given its advances in reducing photon scattering,light absorption,and autofluorescence [1,2].In particular,extensive efforts have been made to produce various NIR-II probes with different emission wavelengths for multiplexing purposes,as practical applications typically require concurrent detection of multiple analytes.

Precise nanomedicine for intelligent therapy of cancer

Precise nanomedicine has been extensively explored for efficient cancer imaging and targeted cancer therapy, as evidenced by a few breakthroughs in their preclinical and clinical explorations. Here, we demonstrate the recent advances of intelligent cancer nanomedicine, and discuss the comprehensive understanding of their structure-function relationship for smart and efficient cancer nanomedicine including various imaging and therapeutic applications, as well as nanotoxicity. In particular, a few emerging strategies that have advanced cancer nanomedicine are also highlighted as the emerging focus such as tumor imprisonment, supramolecular chemotherapy, and DNA nanorobot. The challenge and outlook of some scientific and engineering issues are also discussed in future development. We wish to highlight these new progress of precise nanomedicine with the ultimate goal to inspire more successful explorations of intelligent nanoparticles for future clinical translations.

Intraneuronal tau aggregation induces the integrated stress response in astrocytes

Progressive aggregation of tau protein in neurons is associated with neurodegeneration in tauopathies.Cell non-autonomous disease mechanisms in astrocytes may be important drivers of the disease process but remain largely elusive.Here,we studied cell type-specific responses to intraneuronal tau aggregation prior to neurodegeneration.To this end,we developed a fully human co-culture model of seed-independent intraneuronal tau pathology,which shows no neuron and synapse loss.Using high-content microscopy,we show that intraneuronal tau aggregation induces oxidative stress accompanied by activation of the integrated stress response specifically in astrocytes.This requires the direct co-culture with neurons and is not related to neurodegeneration or extracellular tau levels.Tau-directed antisense therapy reduced intraneuronal tau levels and aggregation and prevented the cell non-autonomous responses in astrocytes.These data identify the astrocytic integrated stress response as a novel disease mechanism activated by intraneuronal tau aggregation.In addition,our data provide the first evidence for the efficacy of tau-directed antisense therapy to target cell autonomous and cell non-autonomous disease pathways in a fully human model of tau pathology.