Carbon capsules with hollow core/mesoporous shell (HCMS) structures have been synthesized (see Figure for schematic) for the first time using solid core/mesoporous shell (SCMS) silica spheres as templates. The capsules have bimodal pore systems consisting of a uniform, tunable, hollow macroscopic core and a mesoporous shell, thus leading to a great variety of possible applications.
Recent advances in sequencing technologies have initiated an era of personal genome sequences. To date, human genome sequences have been reported for individuals with ancestry in three distinct geographical regions: a Yoruba African, two individuals of north-west European origin, and a person from China1–4. Here we provide a highly annotated, whole-genome sequence for a Korean individual, known as AK1. The genome of AK1 was determined by an exacting, combined approach that included whole-genome shotgun sequencing (27.8× coverage), targeted bacterial artificial chromosome sequencing, and high-resolution comparative genomic hybridization using custom microarrays featuring more than 24 million probes. Alignment to the NCBI reference, a composite of several ethnic clades5,6, disclosed nearly 3.45 million single nucleotide polymorphisms (SNPs), including 10,162 non-synonymous SNPs, and 170,202 deletion or insertion polymorphisms (indels). SNP and indel densities were strongly correlated genome-wide. Applying very conservative criteria yielded highly reliable copy number variants for clinical considerations. Potential medical phenotypes were annotated for non-synonymous SNPs, coding domain indels, and structural variants. The integration of several human whole-genome sequences derived from several ethnic groups will assist in understanding genetic ancestry, migration patterns and population bottlenecks.
Mitotic cell division increases tumour mutation burden and copy number load, predictive markers of the clinical benefit of immunotherapy. Cell division correlates also with genomic demethylation involving methylation loss in late-replicating partial methylation domains. Here we find that immunomodulatory pathway genes are concentrated in these domains and transcriptionally repressed in demethylated tumours with CpG island promoter hypermethylation. Global methylation loss correlated with immune evasion signatures independently of mutation burden and aneuploidy. Methylome data of our cohort (n = 60) and a published cohort (n = 81) in lung cancer and a melanoma cohort (n = 40) consistently demonstrated that genomic methylation alterations counteract the contribution of high mutation burden and increase immunotherapeutic resistance. Higher predictive power was observed for methylation loss than mutation burden. We also found that genomic hypomethylation correlates with the immune escape signatures of aneuploid tumours. Hence, DNA methylation alterations implicate epigenetic modulation in precision immunotherapy.
R-TME for rectal cancer is associated with earlier recovery of normal voiding and sexual function compared to patients who underwent L-TME, although this result needs to be verified by larger prospective comparative studies.
The catalytic cysteine of the typical 2-Cys Prx subfamily of peroxiredoxins is occasionally hyperoxidized to cysteine sulfinic acid during the peroxidase catalytic cycle. Sulfinic Prx (Prx-SO 2 H) is reduced back to the active form of the enzyme by sulfiredoxin. The abundance of Prx-SO 2 H was recently shown to oscillate with a period of ∼24 h in human red blood cells (RBCs). We have now investigated the molecular mechanism and physiological relevance of such oscillation in mouse RBCs. Poisoning of RBCs with CO abolished Prx-SO 2 H formation, implicating H 2 O 2 produced from hemoglobin autoxidation in Prx hyperoxidation. RBCs express the closely related PrxI and PrxII isoforms, and analysis of RBCs deficient in either isoform identified PrxII as the hyperoxidized Prx in these cells. Unexpectedly, RBCs from sulfiredoxin-deficient mice also exhibited circadian oscillation of Prx-SO 2 H. Analysis of the effects of protease inhibitors together with the observation that the purified 20S proteasome degraded PrxII-SO 2 H selectively over nonhyperoxidized PrxII suggested that the 20S proteasome is responsible for the decay phase of PrxII-SO 2 H oscillation. About 1% of total PrxII undergoes daily oscillation, resulting in a gradual loss of PrxII during the life span of RBCs. PrxII-SO 2 H was detected in cytosolic and ghost membrane fractions of RBCs, and the amount of membrane-bound PrxII-SO 2 H oscillated in a phase opposite to that of total PrxII-SO 2 H. Our results suggest that membrane association of PrxII-SO 2 H is a tightly controlled process and might play a role in the tuning of RBC function to environmental changes.
Hydrogen peroxide (H2O2) released from mitochondria regulates various cell signaling pathways. Given that H2O2-eliminating enzymes such as peroxiredoxin III (PrxIII) are abundant in mitochondria, however, it has remained unknown how such release can occur. Active PrxIII-SH undergoes reversible inactivation via hyperoxidation to PrxIII-SO2, which is then reduced by sulfiredoxin. We now show that the amounts of PrxIII-SO2 and sulfiredoxin undergo antiphasic circadian oscillation in the mitochondria of specific tissues of mice maintained under normal conditions. Cytosolic sulfiredoxin was found to be imported into the mitochondria via a mechanism that requires formation of a disulfide-linked complex with heat shock protein 90, which is promoted by H2O2 released from mitochondria. The imported sulfiredoxin is degraded by Lon in a manner dependent on PrxIII hyperoxidation state. The coordinated import and degradation of sulfiredoxin provide the basis for sulfiredoxin oscillation and consequent PrxIII-SO2 oscillation in mitochondria and likely result in an oscillatory H2O2 release.
Computed tomography (CT) is the current standard for time-critical decision-making in stroke patients, informing decisions on thrombolytic therapy with tissue plasminogen activator (tPA), which has a narrow therapeutic index. We aimed to develop a CT-based method to directly visualize cerebrovascular thrombi and guide thrombolytic therapy. Glycol-chitosan-coated gold nanoparticles (GC-AuNPs) were synthesized and conjugated to fibrin-targeting peptides, forming fib-GC-AuNP. This targeted imaging agent and non-targeted control agent were characterized in vitro and in vivo in C57Bl/6 mice (n = 107) with FeCl3-induced carotid thrombosis and/or embolic ischemic stroke. Fibrin-binding capacity was superior with fib-GC-AuNPs compared to GC-AuNPs, with thrombi visualized as high density on microCT (mCT). mCT imaging using fib-GC-AuNP allowed the prompt detection and quantification of cerebral thrombi, and monitoring of tPA-mediated thrombolytic effect, which reflected histological stroke outcome. Furthermore, recurrent thrombosis could be diagnosed by mCT without further nanoparticle administration for up to 3 weeks. fib-GC-AuNP-based direct cerebral thrombus imaging greatly enhance the value and information obtainable by regular CT, has multiple uses in basic / translational vascular research, and will likely allow personalized thrombolytic therapy in clinic by a) optimizing tPA-dosing to match thrombus burden, b) enabling the rational triage of patients to more radical therapies such as endovascular clot-retrieval, and c) potentially serving as a theranostic platform for targeted delivery of concurrent thrombolysis.
Increasing evidence exposes a subpopulation of cancer cells, known as cancer stem cells (CSCs), to be critical for the progression of several human malignancies, including glioblastoma multiforme (GBM). CSCs are highly tumorigenic, capable of self-renewal, and resistant to conventional therapies, and thus considered to be one of the key contributors to disease recurrence. In order to elucidate the poorly understood evolutionary path of tumor recurrence and the role of CSCs in this process, we developed patient-derived xenograft GBM recurrent models induced by anti-glioma chemotherapy, temozolomide (TMZ). In this model, we observed a significant phenotypic shift towards an undifferentiated population. We confirmed these findings in vitro as sorted CD133-negative populations cultured in differentiation-forcing media were found to acquire CD133 expression following chemotherapy treatment. To investigate this phenotypic switch at the single cell level, GSC-specific promoter-based reporter systems were engineered to track changes in the GSC population in real time. We observed the active phenotypic and functional switch of single non-stem glioma cells to a stem-like state and that TMZ therapy significantly increased the rate of single-cell conversions. Importantly, we showed the therapy induced hypoxia inducible factors (HIF) 1α and HIF2α play key roles in allowing non-stem glioma cells to acquire stem-like traits, as the expression of both HIFs increase upon TMZ therapy and knockdown of HIFs expression inhibits the interconversion between non-stem glioma cells and GSCs post-therapy. Based on our results, we propose that anti-glioma chemotherapy promotes the accumulation of HIFs in the GBM cells that induces the formation of therapy-resistant GSCs responsible for recurrence.
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