The deposition of insoluble proteinaceous aggregates in the form of amyloidfibrils within the extracellular space of tissues is associated with numerous diseases.The development of molecular approaches to arrest amylo...The deposition of insoluble proteinaceous aggregates in the form of amyloidfibrils within the extracellular space of tissues is associated with numerous diseases.The development of molecular approaches to arrest amyloid formation and prevent cel-lular degeneration remains very challenging due to the complexity of the process of protein aggregation,which encompasses an infinite array of conformations and quaternary structures.Polyanionic biopolymers,such as glycosaminoglycans and RNAs,have been shown to modulate the self-assembly of amyloidogenic polypep-tides and to reduce the toxicity induced by the formation of oligomeric and/or pre-fibrillar proteospecies.This study evaluates the effects of double-stranded DNA(dsDNA)nanostructures(1D,2D,and 3D)on amyloid self-assembly,fibril dis-aggregation,and the cytotoxicity associated with amyloidogenesis.Using the islet amyloid polypeptide(IAPP)whose pancreatic accumulation is the hallmark of type 2 diabetes,it was observed that dsDNA nanostructures inhibit amyloid formation by inducing the formation of spherical complexes in which the peptide adopts a random coil conformation.Interestingly,the DNA nanostructures showed a per-sistent ability to disassemble enzymatically and thermodynamically stable amyloidfibrils into nanoscale DNA/IAPP entities that are fully compatible withβ-pancreatic cells and are biodegradable by proteolysis.Notably,dsDNA nanostructures avidly trapped highly toxic soluble oligomeric species in complete cell culture media and converted them into non-toxic binary complexes.Overall,these results expose the potent modulatory effects of dsDNA on amyloidogenic pathways,and these DNA nanoscaffolds could be used as a source of inspiration for the design of molecules tofight amyloid-related disorders.展开更多
Adenocarcinomas are a major subtype of non-small cell lung cancers （NSCLC） that account for up to 80% of all lung cancers world-wide. It is known that up to 30% of adenocarcinoma pa- tients have oncogenic （tumor-dr...Adenocarcinomas are a major subtype of non-small cell lung cancers （NSCLC） that account for up to 80% of all lung cancers world-wide. It is known that up to 30% of adenocarcinoma pa- tients have oncogenic （tumor-driving） mutations in K-ras and up to 50% have loss of function in the tumor suppressor p53 . Both these alterations, namely activation of Ras and loss of wild type p53 function, have been reported to activate the transcription factor nuclear factor-κB （NFκB） in independent set of studies across many laboratories .展开更多
Photodynamic therapy(PDT) employs accumulation of photosensitizers(PSs) in malignant tumor tissue followed by the light-induced generation of cytotoxic reactive oxygen species to kill the tumor cells. The success of P...Photodynamic therapy(PDT) employs accumulation of photosensitizers(PSs) in malignant tumor tissue followed by the light-induced generation of cytotoxic reactive oxygen species to kill the tumor cells. The success of PDT depends on optimal PS dosage that is matched with the ideal power of light. This in turn depends on PS accumulation in target tissue and light administration time and period.As theranostic nanomedicine is driven by multifunctional therapeutics that aim to achieve targeted tissue delivery and image-guided therapy, fluorescent PS nanoparticle(NP)accumulation in target tissues can be ascertained through fluorescence imaging to optimize the light dose and administration parameters. In this regard, zebrafish larvae provide a unique transparent in vivo platform to monitor fluorescent PS bio-distribution and their therapeutic efficiency. Using fluorescent PS NPs with unique aggregation-induced emission characteristics, we demonstrate for the first time the real-time visualization of polymeric NP accumulation in tumor tissue and, more importantly, the best time to conduct PDT using transgenic zebrafish larvae with inducible liver hyperplasia as an example.展开更多
It has been a dream that theoretical biology can be extensively applied in experimental biology to accelerate the understanding of the sophiscated movements in living organisms. A brave assay and an excellent example ...It has been a dream that theoretical biology can be extensively applied in experimental biology to accelerate the understanding of the sophiscated movements in living organisms. A brave assay and an excellent example were represented by enzymology, in which the well-established physico-chemistry is used to describe, to fit, to predict and to improve enzyme reactions. Before the modern bioinformatics, the developments of the combination of theoretical biology and experimental biology have been mainly limited to various classic formulations. The systematic use of graphic rules by Prof. Kuo-Chen Chou and his co-workers has significantly facilitated to deal with complicated enzyme systems. With the recent fast progress of bioinformatics, prediction of protein structures and various protein attributes have been well established by Chou and co-workers, stimulating the experimental biology. For example, their recent method for predicting protein subcellular localization (one of the important attributes of proteins) has been extensively applied by scientific colleagues, yielding many new results with thousands of citations. The research by Prof. Chou is characterized by introducing novel physical concepts as well as powerful and elegant mathematical methods into important biomedical problems, a focus throughout his career, even when facing enormous difficulties. His efforts in 50 years have greatly helped us to realize the dream to make “theoretical and experimental biology in one”. Prof. Richard Giege is well known for his multi-disciplinary research combining physics, chemistry, enzymology and molecular biology. His major focus of study is on the identity of tRNAs and their interactions with aminoacyl-tRNA synthetases (aaRS), which are of critical importance to the fidelity of protein biosynthesis. He and his colleagues have carried out the first crystallization of a tRNA/aaRS complex, that between tRNAAsp and AspRS from yeast. The determination of the complex structure contributed significantly to under- stand the interaction of protein and RNA. From his fine research, they have also found other biological function of these small RNAs. He has developed in parallel appropriate methods for his research, of which the protein crystallogenesis, a name he has coined, is an excellent example. Now macromolecular crystallogenesis has become a developed science. In fact, such contribution has accelerated the development of protein crystallography, stimulating the study of macromolecular structure and function.展开更多
Objective To evaluate the efficacy of cis-2-dodecenoic acid(BDSF) in the treatment and prevention of vaginal candidiasis in vivo. Methods The activities of different concentrations of BDSF against the virulence factor...Objective To evaluate the efficacy of cis-2-dodecenoic acid(BDSF) in the treatment and prevention of vaginal candidiasis in vivo. Methods The activities of different concentrations of BDSF against the virulence factors of Candida albicans(C. albicans) were determined in vitro. An experimental mouse model of Candida vaginitis was treated with 250 μmol/L BDSF. Treatment efficiency was evaluated in accordance with vaginal fungal burden and inflammation symptoms. Results In vitro experiments indicated that BDSF attenuated the adhesion and damage of C. albicans to epithelial cells by decreasing phospholipase secretion and blocking filament formation. Treatment with 30 μmol/L BDSF reduced the adhesion and damage of C. albicans to epithelial cells by 36.9% and 42.3%, respectively. Treatment with 200 μmol/L BDSF completely inhibited phospholipase activity. In vivo mouse experiments demonstrated that BDSF could effectively eliminate vaginal infection and relieve inflammatory symptoms. Four days of treatment with 250 μmol/L BDSF reduced vaginal fungal loads by 6-fold and depressed inflammation. Moreover, BDSF treatment decreased the expression levels of the inflammatory chemokine-associated genes MCP-1 and IGFBP3 by 2.5-and 2-fold, respectively. Conclusion BDSF is a novel alternative drug that can efficiently control vaginal candidiasis by inhibiting the virulence factors of C. albicans.展开更多
Many enzymes which catalyze the conversion of large substrates are made of several structural domains belonging to the same polypeptide chain. Transfer RNA (tRNA), one of the substrates of the multidomain aminoacyl-tR...Many enzymes which catalyze the conversion of large substrates are made of several structural domains belonging to the same polypeptide chain. Transfer RNA (tRNA), one of the substrates of the multidomain aminoacyl-tRNA synthetases (aaRS), is an L-shaped molecule whose size in one dimension is similar to that of its cognate aaRS. Crystallographic structures of aaRS/tRNA complexes show that these enzymes use several of their structural domains to interact with their cognate tRNA. This mini review discusses first some aspects of the evolution and of the flexibility of the pentadomain bacterial glutamyl-tRNA synthetase (GluRS) revealed by kinetic and interaction studies of complementary truncated forms, and then illustrates how stable analogues of aminoacyl-AMP intermediates have been used to probe conformational changes in the active sites of Escherichia coli GluRS and of the nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) of Pseudomonas aeruginosa.展开更多
Background:Retinol dehydrogenase 8(RDH8)is a 312-amino acid(aa)protein involved in the visual cycle.Bound to the outer segment disk membranes of photoreceptors,it reduces all-trans-retinal to all-trans-retinol1 as one...Background:Retinol dehydrogenase 8(RDH8)is a 312-amino acid(aa)protein involved in the visual cycle.Bound to the outer segment disk membranes of photoreceptors,it reduces all-trans-retinal to all-trans-retinol1 as one of the rate-limiting steps of the visual cycle2.RDH8 is a member of the short-chain dehydrogenase/reductase family.Its C-terminal segment allows its membrane-anchoring through the postulated presence of an amphipathicα-helix and of 1 to 3 acyl groups at positions 299,302 and 3043.The secondary structure and membrane binding characteristics of RDH8 and its C-terminal segment have not yet been described.Methods:To evaluate the membrane binding of RDH8,the full-length protein(aa 1-312),a truncated form(aa 1-296),its C-terminal segment(aa 281-312 and 297-312)as well as different additional variants of this segment were used.The truncated protein binds membranes less efficiently than the full-length form.Thus,the C-terminal segment of RDH8 is essential for the binding and has thus been further examined.The intrinsic fluorescence of tryptophan residues at positions 289 and 310 of the wild-type C-terminal segment of RDH8 and the mutants W289F,W310F and W310R have thus been used to determine their extent of binding to lipid vesicles and to monitor their local environment.Unilamellar lipid vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)or a mixture of POPC and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine(POPS)were used to mimic the phospholipid content of the outer segment disk membranes of photoreceptors.Results:An increase in fluorescence intensity and in fluorescence lifetime is observed upon increasing the concentration of lipid vesicles.These data allowed calculating values of partition coefficient of the C-terminal segment of RDH8 varying between Kp=1.1 E6 to 1.7 E6.It is noteworthy that the observation of a more intense shift to lower wavelengths upon membrane binding of the mutant W310R and W310F indicates a deeper incorporation of the remaining tryptophan residue at position 289 into the lipid bilayer.The secondary structure of the C-terminal segment of RDH8 observed by circular dichroism and infrared spectroscopy shows a superposition ofα-helical,β-turn and unordered structures.Conclusions:The peptides derived from the C-terminal segment of RDH8 show a strong binding to lipid vesicles.These strength of binding is independent of the type of lipid and the presence of a mutation.展开更多
Heat shock proteins (HSPs) play important roles in the mechanism of cellular protection against various environmental stresses. It is well known that accumulation of misfolded proteins in a cell triggers the HSPs expr...Heat shock proteins (HSPs) play important roles in the mechanism of cellular protection against various environmental stresses. It is well known that accumulation of misfolded proteins in a cell triggers the HSPs expression in prokaryotes as well as eukaryotes. In this study, we heterologously expressed two proteins in E. coli, namely, citrate synthase (CpCSY) and malate dehydrogenase (CpMDH) from a psychrophilic bacterium Colwellia psychrerythraea 34H (optimal growth temperature 8°C). Our analyses using circular dichromism along with temperature-dependant enzyme activities measured in purified or direct cell extracts confirmed that the CpCSY and CpMDH are thermolabile and present in misfolded form even at physiological growth temperature. We observed that the cellular levels of HSPs, both GroEL and DnaK cheperonins were increased. Similarly, higher levels were observed for sigma factor s<sup>32</sup> which is specific to heat-shock protein expression. These results suggest that the misfolded-thermolabile proteins expressed in E. coli induced the heat shock response. Furthermore, heat treatment (53°C) to wild type E. coli noticeably delayed their growth recovery but cells expressing CpCSY and CpMDH recovered their growth much faster than that of wild type E. coli. This reveals that the HSPs expressed in response to misfolded-thermolabile proteins protected E. coli against heat-induced damage. This novel approach may be a useful tool for investigating stress-tolerance mechanisms of E. coli.展开更多
In the ever-evolving landscape of cancer research and treatment,the quest for novel and non-invasive imaging techniques has become crucial for accurate diagnosis and effective therapy.This study[1]successfully develop...In the ever-evolving landscape of cancer research and treatment,the quest for novel and non-invasive imaging techniques has become crucial for accurate diagnosis and effective therapy.This study[1]successfully developed a good manufacturing practices(GMP)grade ^(89)Zr-labeled anti-Claudin18.2(CLDN18.2)recombinant humanized antibody TST001.^(89)Zr-DFO-TST001 exhibited high radiochemical purity(>99%)and specific activity(24.15±1.34 GBq/mmol).It demonstrated good specificity and rapid tumor accumulation in vivo and in vivo.Through immuno-PET imaging,it enables non-invasive visualization and quantification of CLDN18.2 expression level in CLDN18.2-positive gastrointestinal tumor models.展开更多
The development of photodynamic therapy(PDT),from its initial discovery of photodynamic effects to its current use in various medical conditions,is a testament to its therapeutic potential.Recent breakthroughs in nano...The development of photodynamic therapy(PDT),from its initial discovery of photodynamic effects to its current use in various medical conditions,is a testament to its therapeutic potential.Recent breakthroughs in nanotechnology have significantly enhanced the effectiveness of PDT.Typical nanomaterials(NMs),including metal-organic frameworks(MOFs),covalent organic frameworks(COFs),and nanozymes have been introduced to enhance the photodynamic efficacy because they can enhance the delivery of PSs,and effectively overcome insufficient targeting specificity,limited tissue penetration depth,and hypoxic microenvironments,thereby amplifying its therapeutic efficacy.However,the clinical application of these NMs in PDT faces several challenges,including concerns regarding biocompatibility,long-term biosafety,and economic feasibility.To further advance PDT,researchers should focus on designing NMs to improve therapeutic outcomes,exploring combination therapies with PDT,and conducting translational clinical trials to validate the safety and therapeutic efficacy of these novel PDT approaches.This review summarizes the recent progress in PDT based on NMs,especially MOFs,COFs and nanozymes and their application in disease treatment.We aim to provide guidance for future research and clinical practice in advancing NMs-enhanced PDT,paving the way for more effective therapeutic strategies.展开更多
It remains a significant challenge to reactivate the cell cycle activity of adult mammalian cardiomyocytes(CMs).This study created a hypo-immunogenic human induced pluripotent stem cell(hiPSC)line using clustered regu...It remains a significant challenge to reactivate the cell cycle activity of adult mammalian cardiomyocytes(CMs).This study created a hypo-immunogenic human induced pluripotent stem cell(hiPSC)line using clustered regularly interspaced palindromic repeats(CRISPR)/Cas9 gene editing to knockoutβ2-microglobulin in hiPSCs(^(B2MKO)hiPSCs)for manufacturing nanovesicles(^(B2MKO)hiPSC-NVs).Approximately 9500^(B2MKO)hiPSC-NVs were produced from a single^(B2MKO)hiPSC.Proteomic analyses indicated that,compared to^(B2MKO)hiPSCs,the cargos of B2MKOhiPSC-NVs were enriched in spindle and chromosomal proteins,as well as proteins that regulate the cell cycle and scavenge reactive oxygen species(ROS).When administrated to hiPSCs derived CMs(hiPSC-CMs),^(B2MKO)hiPSC-NVs reduced lactate dehydrogenase leakage and apoptosis in hypoxia-cultured hiPSC-CMs through activating the AKT pathway,protected hiPSC-CMs from H_(2)O_(2)-induced damage by ROS scavengers in the NV cargo,increased hiPSC-CM proliferation via the YAP pathway,and were hypoimmunogenic when co-cultured with human CD8+T cells or delivered to mice.Furthermore,when^(B2MKO)hiPSC-NVs or 0.9%NaCl were intra-myocardially injected into mice after cardiac ischemia/reperfusion injury,cardiac function and infarct size,assessed 4 weeks later,were significantly improved in the^(B2MKO)hiPSC-NV group,with increased mouse CM survival and cell cycle activity.Thus,the proteins in the^(B2MKO)hiPSC-NV cargos convergently activated the AKT pathway,scavenged ROS to protect CMs,and upregulated YAP signaling to induce CM cell cycle activity.Thus,^(B2MKO)hiPSC-NVs hold great potential for cardiac protection and regeneration.展开更多
The recently developed RNA-guided clustered regularly interspaced short palindromic repeat （CRISPR）/CRISPR-associated 9 （Cas9） nuclease system has progressed to be an invaluable technology for genome manipulation ...The recently developed RNA-guided clustered regularly interspaced short palindromic repeat （CRISPR）/CRISPR-associated 9 （Cas9） nuclease system has progressed to be an invaluable technology for genome manipulation in somatic cell types and germline model organisms. While the unprecedented advance in human embryo gene editing research has great potential in next-generation therapeutics, it raises various ethical concerns that need to be addressed before being translated for clinical use. Here, we discuss the current and potential applications of CRISPR/Cas9 technology and its limitations in clinical applications, as well as ethical and legal considerations in the treatment, disease prevention or disability in somatic cells or human embryo via gene editing.展开更多
Last year, the first attempt to genetically modify human embryos in the United States was reported and sparked a huge debate (Ma et al., 2017). Although the first human germline modification was only performed two yea...Last year, the first attempt to genetically modify human embryos in the United States was reported and sparked a huge debate (Ma et al., 2017). Although the first human germline modification was only performed two years ago, the study showed that rapid adva nces in tech no logy has allowed the rate of off-target effects and mosaicism to be reduced considerably (Liang et al., 2015). Recently, Vertex and CRISPR therapeutics collaborated and developed CTX001, the first CRISPR/Cas9-based therapy, targeting patients with P-thalassemia and have begun phase 1/2 clinical trials. With policies and technologies regarding genome editing both developing rapidly, explorations into the possibility of clinical gene editing for hundreds of hereditary diseases are starting to become achievable. Here, we address the progress of huma n embryo editi ng tech no logies so far and its promise and risks in advancing therapy for hereditary diseases.展开更多
The DNA damage response helps to maintain genome integrity,suppress tumorigenesis,and mediate the effects of radiotherapy and chemotherapy.Our previous studies have shown that Smad1 is upregulated and activated by Atm...The DNA damage response helps to maintain genome integrity,suppress tumorigenesis,and mediate the effects of radiotherapy and chemotherapy.Our previous studies have shown that Smad1 is upregulated and activated by Atm in DNA damage response,which can further bind to p53 and promote p53 stabilization.Herewe report another aspect of the interplay between p53 and Smad1.Comparison of rectal tumor against paired paraneoplastic specimens and analysis of>500 colorectal tumors revealed that Smad1 was upregulated in tumor samples,which was attributable to p53 defects.Using MEFs as a model,we found that knockdown of the elevated Smad1 in p532/2 MEFs promoted cell proliferation,E1A/Ras-induced cell transformation,and tumorigenesis.Mechanistic studies suggest that elevated Smad1 and momentary activation inhibit cell proliferation by upregulating p57Kip2 and enhancing Atm–Chk2 activation.Surprisingly,elevated Smad1 appears to have a negative effect on chemotherapy,as colorectal tumors,primary cancer cells,and cell lines with Smad1 knockdown all showed an increase in chemosensitivity,which could be attributable to elevated p57Kip2.These findings underscore the significance of Smad1–p53 interaction in tumor suppression and reveal an unexpected role for Smad1 in chemoresistance of colorectal cancers.展开更多
The development of efficient contrast agents for tumor-targeted imaging remains a critical challenge in the clinic.Herein,we proposed a tumor-derived extracellular vesicle(EV)-mediated targeting approach to improve in...The development of efficient contrast agents for tumor-targeted imaging remains a critical challenge in the clinic.Herein,we proposed a tumor-derived extracellular vesicle(EV)-mediated targeting approach to improve in vivo tumor imaging using ternary downconversion nanoparticles(DCNPs)with strong near infrared II(NIR-II)luminescence at 1,525 nm.The EVs were metabolically engineered with azide group,followed by in vivo labeling of DCNPs through copper-free click chemistry.By taking advantage of the homologous targeting property of tumor derived EVs,remarkable improvement in the tumor accumulation(6.5%injection dose(ID)/g)was achieved in the subcutaneous colorectal cancer model when compared to that of individual DCNPs via passive targeting(1.1%ID/g).Importantly,such bioorthogonal labeling significantly increased NIR-II luminescence signals and prolonged the retention at tumor sites.Our work demonstrates the great potential of EVs-mediated bioorthogonal approach for in vivo labeling of NIR-II optical probes,which provides a robust tool for tumor-specific imaging and targeted therapy.展开更多
Mitochondrial diseases are maternally inherited hetero- geneous disorders that are primarily caused by mitochondrial DNA （mtDNA） mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy,...Mitochondrial diseases are maternally inherited hetero- geneous disorders that are primarily caused by mitochondrial DNA （mtDNA） mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy, mitochondrial defects can result in a wide spectrum of clinical manifestations. Mitochondria-targeted endonucleases provide an alternative avenue for treating mitochondrial disorders via targeted destruc- tion of the mutant mtDNA and induction of heteroplasmic shifting. Here, we generated mitochondrial disease patient-specific induced pluripotent stem cells （MiPSCs） that harbored a high proportion of m.3243A〉G mtDNA mutations and caused mitochondrial encephalomyopathy and stroke-like episodes （MELAS）. We engineered mitochondrial-targeted transcription activator-like effector nucleases （mitoTALENs） and successfully eliminated the m.3243A〉G mutation in MiPSCs. Off-target mutagenesis was not detected in the targeted MiPSC clones. Utilizing a dual fluorescence iPSC reporter cell line expressing a 3243G mutant mtDNA sequence in the nuclear genome, mitoTALENs displayed a significantly limited ability to target the nuclear genome compared with nuclear-localized TALENs. Moreover, genetically rescued MiPSCs displayed normal mitochondrial respiration and energy production. Moreover, neuronal progenitor cells differentiated from the rescued MiPSCs also demonstrated normal metabolic profiles. Further- more, we successfully achieved reduction in the human m.3243A〉G mtDNA mutation in porcine oocytes via injection of mitoTALEN mRNA. Our study shows the great potential for using mitoTALENs for specific targeting of mutant mtDNA both in iPSCs and mammalian oocytes, which not only provides a new avenue for studying mitochondrial biology and disease but also suggests a potential therapeutic approach for the treatment of mitochondrial disease, as well as the prevention of germline transmission of mutant mtDNA.展开更多
With the advent of rapid automated in silico identification of biosynthetic gene clusters(BGCs),genomics pre-sents vast opportunities to accelerate natural product(NP)discovery.However,prolific NP producers,Strepto-my...With the advent of rapid automated in silico identification of biosynthetic gene clusters(BGCs),genomics pre-sents vast opportunities to accelerate natural product(NP)discovery.However,prolific NP producers,Strepto-myces,are exceptionally GC-rich(>80%)and highly repetitive within BGCs.These pose challenges in sequencing and high-quality genome assembly which are currently circumvented via intensive sequencing.Here,we outline a more cost-effective workflow using multiplex Illumina and Oxford Nanopore sequencing with hybrid long-short read assembly algorithms to generate high quality genomes.Our protocol involves subjecting long read-derived assemblies to up to 4 rounds of polishing with short reads to yield accurate BGC predictions.We successfully sequenced and assembled 8 GC-rich Streptomyces genomes whose lengths range from 7.1 to 12.1 Mb with a median N50 of 8.2 Mb.Taxonomic analysis revealed previous misrepresentation among these strains and allowed us to propose a potentially new species,Streptomyces sydneybrenneri.Further comprehensive characterization of their biosynthetic,pan-genomic and antibiotic resistance features especially for molecules derived from type I polyketide synthase(PKS)BGCs reflected their potential as alternative NP hosts.Thus,the genome assemblies and insights presented here are envisioned to serve as gateway for the scientific community to expand their avenues in NP discovery.展开更多
Tumor hypoxia diminishes the effectiveness of traditional type II photodynamic therapy(PDT)due to oxygen consumption.Type I PDT,which can operate independently of oxygen,is a viable option for treating hypoxic tumors....Tumor hypoxia diminishes the effectiveness of traditional type II photodynamic therapy(PDT)due to oxygen consumption.Type I PDT,which can operate independently of oxygen,is a viable option for treating hypoxic tumors.In this study,we have designed and synthesized JSK@PEG-IR820 NPs that are responsive to the tumor microenvironment(TME)to enhance type I PDT through glutathione(GSH)depletion.Our approach aims to expand the sources of therapeutic benefits by promoting the generation of superoxide radicals(O_(2)^(-).)while minimizing their consumption.The diisopropyl group within PEG-IR820 serves a dual purpose:it functions as a pH sensor for the disassembly of the NPs to release JSK and enhances intermolecular electron transfer to IR820,facilitating efficient O_(2)^(-).generation.Simultaneously,the release of JSK leads to GSH depletion,resulting in the generation of nitric oxide(NO).This,in turn,contributes to the formation of highly cytotoxic peroxynitrite(ONOO^(-).),thereby enhancing the therapeutic efficacy of these NPs.NIR-II fluorescence imaging guided therapy has achieved successful tumor eradication with the assistance of laser therapy.展开更多
As a newly identified transcription factor in Candida albcians, CaSfl1 has been shown to be involved in cell flocculation and filamentation and in the negative regulation of several genes involved in hyphal growth. In...As a newly identified transcription factor in Candida albcians, CaSfl1 has been shown to be involved in cell flocculation and filamentation and in the negative regulation of several genes involved in hyphal growth. In this study, we constructed Casfl1△/△ mutants and confirmed that deletion of this gene indeed affected cell flocculation and filamentation. In addition, by RT-PCR we found that while Casfl1 repressed the expression of several hypha-specific genes including HWP1, ECE1, ALS1, ALS3, and FLO8, it strongly activated the expression of the heat-shock protein genes HSP30 and HSP90 under certain stress conditions. Therefore, we propose that CaSfl1 can act as both positive and negative regulators, thereby playing a dual role in transcriptional controls in Candida albicans.展开更多
基金Natural Sciences and Engineering Research Council of Canada,Grant/Award Numbers:RGPIN-2018-06209,RGPIN-2021-03301,RGPIN-2018-05799。
文摘The deposition of insoluble proteinaceous aggregates in the form of amyloidfibrils within the extracellular space of tissues is associated with numerous diseases.The development of molecular approaches to arrest amyloid formation and prevent cel-lular degeneration remains very challenging due to the complexity of the process of protein aggregation,which encompasses an infinite array of conformations and quaternary structures.Polyanionic biopolymers,such as glycosaminoglycans and RNAs,have been shown to modulate the self-assembly of amyloidogenic polypep-tides and to reduce the toxicity induced by the formation of oligomeric and/or pre-fibrillar proteospecies.This study evaluates the effects of double-stranded DNA(dsDNA)nanostructures(1D,2D,and 3D)on amyloid self-assembly,fibril dis-aggregation,and the cytotoxicity associated with amyloidogenesis.Using the islet amyloid polypeptide(IAPP)whose pancreatic accumulation is the hallmark of type 2 diabetes,it was observed that dsDNA nanostructures inhibit amyloid formation by inducing the formation of spherical complexes in which the peptide adopts a random coil conformation.Interestingly,the DNA nanostructures showed a per-sistent ability to disassemble enzymatically and thermodynamically stable amyloidfibrils into nanoscale DNA/IAPP entities that are fully compatible withβ-pancreatic cells and are biodegradable by proteolysis.Notably,dsDNA nanostructures avidly trapped highly toxic soluble oligomeric species in complete cell culture media and converted them into non-toxic binary complexes.Overall,these results expose the potent modulatory effects of dsDNA on amyloidogenic pathways,and these DNA nanoscaffolds could be used as a source of inspiration for the design of molecules tofight amyloid-related disorders.
文摘Adenocarcinomas are a major subtype of non-small cell lung cancers （NSCLC） that account for up to 80% of all lung cancers world-wide. It is known that up to 30% of adenocarcinoma pa- tients have oncogenic （tumor-driving） mutations in K-ras and up to 50% have loss of function in the tumor suppressor p53 . Both these alterations, namely activation of Ras and loss of wild type p53 function, have been reported to activate the transcription factor nuclear factor-κB （NFκB） in independent set of studies across many laboratories .
基金financial support from National Research Foundation Investigatorship (R279-000-444-281)National University of Singapore (R279-000-482-133)
文摘Photodynamic therapy(PDT) employs accumulation of photosensitizers(PSs) in malignant tumor tissue followed by the light-induced generation of cytotoxic reactive oxygen species to kill the tumor cells. The success of PDT depends on optimal PS dosage that is matched with the ideal power of light. This in turn depends on PS accumulation in target tissue and light administration time and period.As theranostic nanomedicine is driven by multifunctional therapeutics that aim to achieve targeted tissue delivery and image-guided therapy, fluorescent PS nanoparticle(NP)accumulation in target tissues can be ascertained through fluorescence imaging to optimize the light dose and administration parameters. In this regard, zebrafish larvae provide a unique transparent in vivo platform to monitor fluorescent PS bio-distribution and their therapeutic efficiency. Using fluorescent PS NPs with unique aggregation-induced emission characteristics, we demonstrate for the first time the real-time visualization of polymeric NP accumulation in tumor tissue and, more importantly, the best time to conduct PDT using transgenic zebrafish larvae with inducible liver hyperplasia as an example.
文摘It has been a dream that theoretical biology can be extensively applied in experimental biology to accelerate the understanding of the sophiscated movements in living organisms. A brave assay and an excellent example were represented by enzymology, in which the well-established physico-chemistry is used to describe, to fit, to predict and to improve enzyme reactions. Before the modern bioinformatics, the developments of the combination of theoretical biology and experimental biology have been mainly limited to various classic formulations. The systematic use of graphic rules by Prof. Kuo-Chen Chou and his co-workers has significantly facilitated to deal with complicated enzyme systems. With the recent fast progress of bioinformatics, prediction of protein structures and various protein attributes have been well established by Chou and co-workers, stimulating the experimental biology. For example, their recent method for predicting protein subcellular localization (one of the important attributes of proteins) has been extensively applied by scientific colleagues, yielding many new results with thousands of citations. The research by Prof. Chou is characterized by introducing novel physical concepts as well as powerful and elegant mathematical methods into important biomedical problems, a focus throughout his career, even when facing enormous difficulties. His efforts in 50 years have greatly helped us to realize the dream to make “theoretical and experimental biology in one”. Prof. Richard Giege is well known for his multi-disciplinary research combining physics, chemistry, enzymology and molecular biology. His major focus of study is on the identity of tRNAs and their interactions with aminoacyl-tRNA synthetases (aaRS), which are of critical importance to the fidelity of protein biosynthesis. He and his colleagues have carried out the first crystallization of a tRNA/aaRS complex, that between tRNAAsp and AspRS from yeast. The determination of the complex structure contributed significantly to under- stand the interaction of protein and RNA. From his fine research, they have also found other biological function of these small RNAs. He has developed in parallel appropriate methods for his research, of which the protein crystallogenesis, a name he has coined, is an excellent example. Now macromolecular crystallogenesis has become a developed science. In fact, such contribution has accelerated the development of protein crystallography, stimulating the study of macromolecular structure and function.
基金financially supported by the National Natural Science Foundation of China [81273409]the Program for Changjiang Scholars and Innovative Research Team in University [IRT_15R37]the Ministry of Science and Technology of China [2017YFA0205301]
文摘Objective To evaluate the efficacy of cis-2-dodecenoic acid(BDSF) in the treatment and prevention of vaginal candidiasis in vivo. Methods The activities of different concentrations of BDSF against the virulence factors of Candida albicans(C. albicans) were determined in vitro. An experimental mouse model of Candida vaginitis was treated with 250 μmol/L BDSF. Treatment efficiency was evaluated in accordance with vaginal fungal burden and inflammation symptoms. Results In vitro experiments indicated that BDSF attenuated the adhesion and damage of C. albicans to epithelial cells by decreasing phospholipase secretion and blocking filament formation. Treatment with 30 μmol/L BDSF reduced the adhesion and damage of C. albicans to epithelial cells by 36.9% and 42.3%, respectively. Treatment with 200 μmol/L BDSF completely inhibited phospholipase activity. In vivo mouse experiments demonstrated that BDSF could effectively eliminate vaginal infection and relieve inflammatory symptoms. Four days of treatment with 250 μmol/L BDSF reduced vaginal fungal loads by 6-fold and depressed inflammation. Moreover, BDSF treatment decreased the expression levels of the inflammatory chemokine-associated genes MCP-1 and IGFBP3 by 2.5-and 2-fold, respectively. Conclusion BDSF is a novel alternative drug that can efficiently control vaginal candidiasis by inhibiting the virulence factors of C. albicans.
文摘Many enzymes which catalyze the conversion of large substrates are made of several structural domains belonging to the same polypeptide chain. Transfer RNA (tRNA), one of the substrates of the multidomain aminoacyl-tRNA synthetases (aaRS), is an L-shaped molecule whose size in one dimension is similar to that of its cognate aaRS. Crystallographic structures of aaRS/tRNA complexes show that these enzymes use several of their structural domains to interact with their cognate tRNA. This mini review discusses first some aspects of the evolution and of the flexibility of the pentadomain bacterial glutamyl-tRNA synthetase (GluRS) revealed by kinetic and interaction studies of complementary truncated forms, and then illustrates how stable analogues of aminoacyl-AMP intermediates have been used to probe conformational changes in the active sites of Escherichia coli GluRS and of the nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) of Pseudomonas aeruginosa.
文摘Background:Retinol dehydrogenase 8(RDH8)is a 312-amino acid(aa)protein involved in the visual cycle.Bound to the outer segment disk membranes of photoreceptors,it reduces all-trans-retinal to all-trans-retinol1 as one of the rate-limiting steps of the visual cycle2.RDH8 is a member of the short-chain dehydrogenase/reductase family.Its C-terminal segment allows its membrane-anchoring through the postulated presence of an amphipathicα-helix and of 1 to 3 acyl groups at positions 299,302 and 3043.The secondary structure and membrane binding characteristics of RDH8 and its C-terminal segment have not yet been described.Methods:To evaluate the membrane binding of RDH8,the full-length protein(aa 1-312),a truncated form(aa 1-296),its C-terminal segment(aa 281-312 and 297-312)as well as different additional variants of this segment were used.The truncated protein binds membranes less efficiently than the full-length form.Thus,the C-terminal segment of RDH8 is essential for the binding and has thus been further examined.The intrinsic fluorescence of tryptophan residues at positions 289 and 310 of the wild-type C-terminal segment of RDH8 and the mutants W289F,W310F and W310R have thus been used to determine their extent of binding to lipid vesicles and to monitor their local environment.Unilamellar lipid vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)or a mixture of POPC and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine(POPS)were used to mimic the phospholipid content of the outer segment disk membranes of photoreceptors.Results:An increase in fluorescence intensity and in fluorescence lifetime is observed upon increasing the concentration of lipid vesicles.These data allowed calculating values of partition coefficient of the C-terminal segment of RDH8 varying between Kp=1.1 E6 to 1.7 E6.It is noteworthy that the observation of a more intense shift to lower wavelengths upon membrane binding of the mutant W310R and W310F indicates a deeper incorporation of the remaining tryptophan residue at position 289 into the lipid bilayer.The secondary structure of the C-terminal segment of RDH8 observed by circular dichroism and infrared spectroscopy shows a superposition ofα-helical,β-turn and unordered structures.Conclusions:The peptides derived from the C-terminal segment of RDH8 show a strong binding to lipid vesicles.These strength of binding is independent of the type of lipid and the presence of a mutation.
文摘Heat shock proteins (HSPs) play important roles in the mechanism of cellular protection against various environmental stresses. It is well known that accumulation of misfolded proteins in a cell triggers the HSPs expression in prokaryotes as well as eukaryotes. In this study, we heterologously expressed two proteins in E. coli, namely, citrate synthase (CpCSY) and malate dehydrogenase (CpMDH) from a psychrophilic bacterium Colwellia psychrerythraea 34H (optimal growth temperature 8°C). Our analyses using circular dichromism along with temperature-dependant enzyme activities measured in purified or direct cell extracts confirmed that the CpCSY and CpMDH are thermolabile and present in misfolded form even at physiological growth temperature. We observed that the cellular levels of HSPs, both GroEL and DnaK cheperonins were increased. Similarly, higher levels were observed for sigma factor s<sup>32</sup> which is specific to heat-shock protein expression. These results suggest that the misfolded-thermolabile proteins expressed in E. coli induced the heat shock response. Furthermore, heat treatment (53°C) to wild type E. coli noticeably delayed their growth recovery but cells expressing CpCSY and CpMDH recovered their growth much faster than that of wild type E. coli. This reveals that the HSPs expressed in response to misfolded-thermolabile proteins protected E. coli against heat-induced damage. This novel approach may be a useful tool for investigating stress-tolerance mechanisms of E. coli.
基金supported by the National University of Singapore(Grant Nos.:NUHSRO/2021/097/Startup/13,NUHSRO/2020/133/Startup/08,NUHSRO/2023/008/NUSMed/TCE/LOA,NUHSRO/2021/034/TRP/09/Nanomedicine,and NUHSRO/2021/044/Kickstart/09/LOA)National Medical Research Council(Grant Nos.:OFYIRG23jan-0025,OFYIRG23jan-0017,MOH-001254-01,and CG21APR1005)+2 种基金Singapore Ministry of Education Academic Research Fund(Grant Nos.:NUHSRO/2022/093/T1/Seed-Sep/06 and MOE-000387-01)National Research Foundation(Grant No.:CRP28-2022RS-0001),National Natural Science Foundation of China(Grant No.:82202206)Beijing Natural Science Foundation(Grant No.:7224365).
文摘In the ever-evolving landscape of cancer research and treatment,the quest for novel and non-invasive imaging techniques has become crucial for accurate diagnosis and effective therapy.This study[1]successfully developed a good manufacturing practices(GMP)grade ^(89)Zr-labeled anti-Claudin18.2(CLDN18.2)recombinant humanized antibody TST001.^(89)Zr-DFO-TST001 exhibited high radiochemical purity(>99%)and specific activity(24.15±1.34 GBq/mmol).It demonstrated good specificity and rapid tumor accumulation in vivo and in vivo.Through immuno-PET imaging,it enables non-invasive visualization and quantification of CLDN18.2 expression level in CLDN18.2-positive gastrointestinal tumor models.
基金supported by National University of Singapore(NUHSRO/2020/133/Startup/08,NUHSRO/2023/008/NUSMed/TCE/LOA,NUHSRO/2021/034/TRP/09/Nanomedicine,NUHSRO/2021/044/Kickstart/09/L0A,23-0173-A0001)National Medical Research Council(MOH-001388-00,CG21APR1005,MOH-001500-00,MOH-001609-00)+4 种基金Singapore Ministry of Education(M0E-000387-00)National Research Foundation(NRF-000352-00)the China Postdoctoral Science Foundation(2023M742924)the Postdoctoral Fellowship Program of CPSF(GZC20231426)the National Natural Science Foundation of China(82403144).
文摘The development of photodynamic therapy(PDT),from its initial discovery of photodynamic effects to its current use in various medical conditions,is a testament to its therapeutic potential.Recent breakthroughs in nanotechnology have significantly enhanced the effectiveness of PDT.Typical nanomaterials(NMs),including metal-organic frameworks(MOFs),covalent organic frameworks(COFs),and nanozymes have been introduced to enhance the photodynamic efficacy because they can enhance the delivery of PSs,and effectively overcome insufficient targeting specificity,limited tissue penetration depth,and hypoxic microenvironments,thereby amplifying its therapeutic efficacy.However,the clinical application of these NMs in PDT faces several challenges,including concerns regarding biocompatibility,long-term biosafety,and economic feasibility.To further advance PDT,researchers should focus on designing NMs to improve therapeutic outcomes,exploring combination therapies with PDT,and conducting translational clinical trials to validate the safety and therapeutic efficacy of these novel PDT approaches.This review summarizes the recent progress in PDT based on NMs,especially MOFs,COFs and nanozymes and their application in disease treatment.We aim to provide guidance for future research and clinical practice in advancing NMs-enhanced PDT,paving the way for more effective therapeutic strategies.
基金the National Heart, Lung, and Blood Institute Grant Numbers: U01HL134764, NIH P01 HL160476 , R01HL131017, R01HL149137.
文摘It remains a significant challenge to reactivate the cell cycle activity of adult mammalian cardiomyocytes(CMs).This study created a hypo-immunogenic human induced pluripotent stem cell(hiPSC)line using clustered regularly interspaced palindromic repeats(CRISPR)/Cas9 gene editing to knockoutβ2-microglobulin in hiPSCs(^(B2MKO)hiPSCs)for manufacturing nanovesicles(^(B2MKO)hiPSC-NVs).Approximately 9500^(B2MKO)hiPSC-NVs were produced from a single^(B2MKO)hiPSC.Proteomic analyses indicated that,compared to^(B2MKO)hiPSCs,the cargos of B2MKOhiPSC-NVs were enriched in spindle and chromosomal proteins,as well as proteins that regulate the cell cycle and scavenge reactive oxygen species(ROS).When administrated to hiPSCs derived CMs(hiPSC-CMs),^(B2MKO)hiPSC-NVs reduced lactate dehydrogenase leakage and apoptosis in hypoxia-cultured hiPSC-CMs through activating the AKT pathway,protected hiPSC-CMs from H_(2)O_(2)-induced damage by ROS scavengers in the NV cargo,increased hiPSC-CM proliferation via the YAP pathway,and were hypoimmunogenic when co-cultured with human CD8+T cells or delivered to mice.Furthermore,when^(B2MKO)hiPSC-NVs or 0.9%NaCl were intra-myocardially injected into mice after cardiac ischemia/reperfusion injury,cardiac function and infarct size,assessed 4 weeks later,were significantly improved in the^(B2MKO)hiPSC-NV group,with increased mouse CM survival and cell cycle activity.Thus,the proteins in the^(B2MKO)hiPSC-NV cargos convergently activated the AKT pathway,scavenged ROS to protect CMs,and upregulated YAP signaling to induce CM cell cycle activity.Thus,^(B2MKO)hiPSC-NVs hold great potential for cardiac protection and regeneration.
文摘The recently developed RNA-guided clustered regularly interspaced short palindromic repeat （CRISPR）/CRISPR-associated 9 （Cas9） nuclease system has progressed to be an invaluable technology for genome manipulation in somatic cell types and germline model organisms. While the unprecedented advance in human embryo gene editing research has great potential in next-generation therapeutics, it raises various ethical concerns that need to be addressed before being translated for clinical use. Here, we discuss the current and potential applications of CRISPR/Cas9 technology and its limitations in clinical applications, as well as ethical and legal considerations in the treatment, disease prevention or disability in somatic cells or human embryo via gene editing.
基金National Key R&D Program of China (2016YFC1000601)National Natural Science Foundation of China (Grant Nos. 81570101, 81728002, 81741006 and 81871162)+1 种基金Guan gdo ng Province Science and Tech no logy Project (2017A020214005)the Guangzhou Science and Technology Project (201803010048).
文摘Last year, the first attempt to genetically modify human embryos in the United States was reported and sparked a huge debate (Ma et al., 2017). Although the first human germline modification was only performed two years ago, the study showed that rapid adva nces in tech no logy has allowed the rate of off-target effects and mosaicism to be reduced considerably (Liang et al., 2015). Recently, Vertex and CRISPR therapeutics collaborated and developed CTX001, the first CRISPR/Cas9-based therapy, targeting patients with P-thalassemia and have begun phase 1/2 clinical trials. With policies and technologies regarding genome editing both developing rapidly, explorations into the possibility of clinical gene editing for hundreds of hereditary diseases are starting to become achievable. Here, we address the progress of huma n embryo editi ng tech no logies so far and its promise and risks in advancing therapy for hereditary diseases.
基金This work was supported by grants from the National Natural Science Foundation of China(81130039,31300684,and 81421061)the National Key Basic Research Program of China(2012CB966901 and 2014CB942900)Program of Shanghai Subject Chief Scientist(13XD1401900).
文摘The DNA damage response helps to maintain genome integrity,suppress tumorigenesis,and mediate the effects of radiotherapy and chemotherapy.Our previous studies have shown that Smad1 is upregulated and activated by Atm in DNA damage response,which can further bind to p53 and promote p53 stabilization.Herewe report another aspect of the interplay between p53 and Smad1.Comparison of rectal tumor against paired paraneoplastic specimens and analysis of>500 colorectal tumors revealed that Smad1 was upregulated in tumor samples,which was attributable to p53 defects.Using MEFs as a model,we found that knockdown of the elevated Smad1 in p532/2 MEFs promoted cell proliferation,E1A/Ras-induced cell transformation,and tumorigenesis.Mechanistic studies suggest that elevated Smad1 and momentary activation inhibit cell proliferation by upregulating p57Kip2 and enhancing Atm–Chk2 activation.Surprisingly,elevated Smad1 appears to have a negative effect on chemotherapy,as colorectal tumors,primary cancer cells,and cell lines with Smad1 knockdown all showed an increase in chemosensitivity,which could be attributable to elevated p57Kip2.These findings underscore the significance of Smad1–p53 interaction in tumor suppression and reveal an unexpected role for Smad1 in chemoresistance of colorectal cancers.
基金supported by the China Postdoctoral Science Foundation(No.2022M712157)China National Postdoctoral Program for Innovative Talents(No.BX20220215)+5 种基金China Scientific Research Foundation of Peking University Shenzhen Hospital(No.KYQD202100X)the National Natural Science Foundation of China(No.32101074)Shenzhen Science and Technology Innovation Committee Discipline Layout Project(No.JCYJ20170816105345191)National University of Singapore Start-up Grant(No.NUHSRO/2020/133/Startup/08)NUS School of Medicine Nanomedicine Translational Research Programme(No.NUHSRO/2021/034/TRP/09/Nanomedicine)the National Medical Research Council(NMRC)Centre Grant Programme(No.CG21APR1005).
文摘The development of efficient contrast agents for tumor-targeted imaging remains a critical challenge in the clinic.Herein,we proposed a tumor-derived extracellular vesicle(EV)-mediated targeting approach to improve in vivo tumor imaging using ternary downconversion nanoparticles(DCNPs)with strong near infrared II(NIR-II)luminescence at 1,525 nm.The EVs were metabolically engineered with azide group,followed by in vivo labeling of DCNPs through copper-free click chemistry.By taking advantage of the homologous targeting property of tumor derived EVs,remarkable improvement in the tumor accumulation(6.5%injection dose(ID)/g)was achieved in the subcutaneous colorectal cancer model when compared to that of individual DCNPs via passive targeting(1.1%ID/g).Importantly,such bioorthogonal labeling significantly increased NIR-II luminescence signals and prolonged the retention at tumor sites.Our work demonstrates the great potential of EVs-mediated bioorthogonal approach for in vivo labeling of NIR-II optical probes,which provides a robust tool for tumor-specific imaging and targeted therapy.
基金This work was supported in part by the ＂Reproductive health and major birth defects prevention and control research＂ Key Special Fund （No. 2016YFC1000601）, the National Natural Science Foundation of China （Grant Nos. 31371521, 81370766, 81401254, 81570101, 81671121, 31601187, 81521002）, the Guangdong Province Science and Technology Project （2014TQ01R683, 2017A020 214005, 2016A020216023, 2015A030310119, 2016B030229008）, the Bureau of Science and Technology of Guangzhou Municipality （201505011111498）, the ＂Reproductive health and major birth defects prevention and control research＂ Key Special Fund （Nos. 2016YFC1000201 and 2016YFC1000302）, the Ministry of Science and Technology of China Grants （973 program 2014CB943203）, and the Beijing Nova Program （xxjh2015011）.
文摘Mitochondrial diseases are maternally inherited hetero- geneous disorders that are primarily caused by mitochondrial DNA （mtDNA） mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy, mitochondrial defects can result in a wide spectrum of clinical manifestations. Mitochondria-targeted endonucleases provide an alternative avenue for treating mitochondrial disorders via targeted destruc- tion of the mutant mtDNA and induction of heteroplasmic shifting. Here, we generated mitochondrial disease patient-specific induced pluripotent stem cells （MiPSCs） that harbored a high proportion of m.3243A〉G mtDNA mutations and caused mitochondrial encephalomyopathy and stroke-like episodes （MELAS）. We engineered mitochondrial-targeted transcription activator-like effector nucleases （mitoTALENs） and successfully eliminated the m.3243A〉G mutation in MiPSCs. Off-target mutagenesis was not detected in the targeted MiPSC clones. Utilizing a dual fluorescence iPSC reporter cell line expressing a 3243G mutant mtDNA sequence in the nuclear genome, mitoTALENs displayed a significantly limited ability to target the nuclear genome compared with nuclear-localized TALENs. Moreover, genetically rescued MiPSCs displayed normal mitochondrial respiration and energy production. Moreover, neuronal progenitor cells differentiated from the rescued MiPSCs also demonstrated normal metabolic profiles. Further- more, we successfully achieved reduction in the human m.3243A〉G mtDNA mutation in porcine oocytes via injection of mitoTALEN mRNA. Our study shows the great potential for using mitoTALENs for specific targeting of mutant mtDNA both in iPSCs and mammalian oocytes, which not only provides a new avenue for studying mitochondrial biology and disease but also suggests a potential therapeutic approach for the treatment of mitochondrial disease, as well as the prevention of germline transmission of mutant mtDNA.
基金supported by National Research Foundation,Singapore(NRF-CRP19-2017-05-00)Agency for Science,Technology and Research(A*STAR),Singapore(#21719).
文摘With the advent of rapid automated in silico identification of biosynthetic gene clusters(BGCs),genomics pre-sents vast opportunities to accelerate natural product(NP)discovery.However,prolific NP producers,Strepto-myces,are exceptionally GC-rich(>80%)and highly repetitive within BGCs.These pose challenges in sequencing and high-quality genome assembly which are currently circumvented via intensive sequencing.Here,we outline a more cost-effective workflow using multiplex Illumina and Oxford Nanopore sequencing with hybrid long-short read assembly algorithms to generate high quality genomes.Our protocol involves subjecting long read-derived assemblies to up to 4 rounds of polishing with short reads to yield accurate BGC predictions.We successfully sequenced and assembled 8 GC-rich Streptomyces genomes whose lengths range from 7.1 to 12.1 Mb with a median N50 of 8.2 Mb.Taxonomic analysis revealed previous misrepresentation among these strains and allowed us to propose a potentially new species,Streptomyces sydneybrenneri.Further comprehensive characterization of their biosynthetic,pan-genomic and antibiotic resistance features especially for molecules derived from type I polyketide synthase(PKS)BGCs reflected their potential as alternative NP hosts.Thus,the genome assemblies and insights presented here are envisioned to serve as gateway for the scientific community to expand their avenues in NP discovery.
基金the National University of Singapore(NUHSRO/2020/133/Startup/08,NUHSRO/2023/008/NUSMed/TCE/LOA,NUHSRO/2021/034/TRP/09/Nanomedicine)National Medical Research Council(MOH-001388-00,MOH-001041,CG21APR1005)+2 种基金Singapore Ministry of Education(MOE-000387-00)National Research Foundation(NRF-000352-00)the Open Fund Young Individual Research Grant of Singapore(MOH-001127-01).
文摘Tumor hypoxia diminishes the effectiveness of traditional type II photodynamic therapy(PDT)due to oxygen consumption.Type I PDT,which can operate independently of oxygen,is a viable option for treating hypoxic tumors.In this study,we have designed and synthesized JSK@PEG-IR820 NPs that are responsive to the tumor microenvironment(TME)to enhance type I PDT through glutathione(GSH)depletion.Our approach aims to expand the sources of therapeutic benefits by promoting the generation of superoxide radicals(O_(2)^(-).)while minimizing their consumption.The diisopropyl group within PEG-IR820 serves a dual purpose:it functions as a pH sensor for the disassembly of the NPs to release JSK and enhances intermolecular electron transfer to IR820,facilitating efficient O_(2)^(-).generation.Simultaneously,the release of JSK leads to GSH depletion,resulting in the generation of nitric oxide(NO).This,in turn,contributes to the formation of highly cytotoxic peroxynitrite(ONOO^(-).),thereby enhancing the therapeutic efficacy of these NPs.NIR-II fluorescence imaging guided therapy has achieved successful tumor eradication with the assistance of laser therapy.
基金the Joint Research Fund for Overseas Natural Science of China (Grant No. 30228001)National Basic Research Program of China (Grant No. 2007CB914401)
文摘As a newly identified transcription factor in Candida albcians, CaSfl1 has been shown to be involved in cell flocculation and filamentation and in the negative regulation of several genes involved in hyphal growth. In this study, we constructed Casfl1△/△ mutants and confirmed that deletion of this gene indeed affected cell flocculation and filamentation. In addition, by RT-PCR we found that while Casfl1 repressed the expression of several hypha-specific genes including HWP1, ECE1, ALS1, ALS3, and FLO8, it strongly activated the expression of the heat-shock protein genes HSP30 and HSP90 under certain stress conditions. Therefore, we propose that CaSfl1 can act as both positive and negative regulators, thereby playing a dual role in transcriptional controls in Candida albicans.
