Aging and comprehensive molecular profiling in acute myeloid leukemia.

Acute myeloid leukemia (AML) is an aging-related and heterogeneous hematopoietic malignancy. In this study, a total of 1,474 newly diagnosed AML patients with RNA sequencing data were enrolled, and targeted or whole exome sequencing data were obtained in 94% cases. The correlation of aging-related factors including age and clonal hematopoiesis (CH), gender, and genomic/transcriptomic profiles (gene fusions, genetic mutations, and gene expression networks or pathways) was systematically analyzed. Overall, AML patients aged 60 y and older showed an apparently dismal prognosis. Alongside age, the frequency of gene fusions defined in the World Health Organization classification decreased, while the positive rate of gene mutations, especially CH-related ones, increased. Additionally, the number of genetic mutations was higher in gene fusion-negative (GF-) patients than those with GF. Based on the status of CH- and myelodysplastic syndromes (MDS)-related mutations, three mutant subgroups were identified among the GF- AML cohort, namely, CH-AML, CH-MDS-AML, and other GF- AML. Notably, CH-MDS-AML demonstrated a predominance of elderly and male cases, cytopenia, and significantly adverse clinical outcomes. Besides, gene expression networks including HOXA/B, platelet factors, and inflammatory responses were most striking features associated with aging and poor prognosis in AML. Our work has thus unraveled the intricate regulatory circuitry of interactions among different age, gender, and molecular groups of AML.

Combination of eriocalyxin B and homoharringtonine exerts synergistic anti-tumor effects against t(8;21) AML.

Understanding the molecular pathogenesis of acute myeloid leukemia (AML) with well-defined genomic abnormalities has facilitated the development of targeted therapeutics. Patients with t(8;21) AML frequently harbor a fusion gene RUNX1-RUNX1T1 and KIT mutations as "secondary hit", making the disease one of the ideal models for exploring targeted treatment options in AML. In this study we investigated the combination therapy of agents targeting RUNX1-RUNX1T1 and KIT in the treatment of t(8;21) AML with KIT mutations. We showed that the combination of eriocalyxin B (EriB) and homoharringtonine (HHT) exerted synergistic therapeutic effects by dual inhibition of RUNX1-RUNX1T1 and KIT proteins in Kasumi-1 and SKNO-1 cells in vitro. In Kasumi-1 cells, the combination of EriB and HHT could perturb the RUNX1-RUNX1T1-responsible transcriptional network by destabilizing RUNX1-RUNX1T1 transcription factor complex (AETFC), forcing RUNX1-RUNX1T1 leaving from the chromatin, triggering cell cycle arrest and apoptosis. Meanwhile, EriB combined with HHT activated JNK signaling, resulting in the eventual degradation of RUNX1-RUNX1T1 by caspase-3. In addition, HHT and EriB inhibited NF-κB pathway through blocking p65 nuclear translocation in two different manners, to synergistically interfere with the transcription of KIT. In mice co-expressing RUNX1-RUNX1T1 and KITN822K, co-administration of EriB and HHT significantly prolonged survival of the mice by targeting CD34+CD38- leukemic cells. The synergistic effects of the two drugs were also observed in bone marrow mononuclear cells (BMMCs) of t(8;21) AML patients. Collectively, this study reveals the synergistic mechanism of the combination regimen of EriB and HHT in t(8;21) AML, providing new insight into optimizing targeted treatment of AML.

Risk analysis of depression among adult patients with epilepsy of different sex: a retrospective single-center study from China.

Objective: To determine sex differences in the prevalence of depression and assess the risk factors for depression among adult patients with epilepsy from the Dali area of China. Methods: We retrospectively analyzed the clinical data of adult patients with epilepsy who visited the First Affiliated Hospital of Dali University from January 2017 to January 2022. Patient Health Questionnaire-9 was used to assess depressive symptoms in patients with epilepsy. The risk factors of depression were analyzed by binary logistic regression among different sex in patients with epilepsy. Results: There were significant sex differences in depression in patients with epilepsy (p < 0.001), and females were 4.27 times more likely to suffer from depression than males (95% confidence interval: 3.70-4.92). The risk factors for depression among female patients with epilepsy included occupation (p < 0.001), years with epilepsy (p < 0.001), seizure frequency (p < 0.001), seizure type (p < 0.001), etiology (p < 0.001), number of antiseizure medications used (p < 0.001), antiseizure medications (p < 0.001), and electroencephalogram findings (p < 0.001). The risk factors for depression among male patients with epilepsy included age (p < 0.001), ethnicity (p < 0.001), occupation (p < 0.001), years with epilepsy (p < 0.001), seizure frequency (p < 0.001), seizure type (p < 0.001), etiology (p < 0.001), number of antiseizure medications used (p < 0.001), antiseizure medications (p < 0.001), and electroencephalogram findings (p < 0.001). Conclusion: Adult female patients with epilepsy had a higher risk of depression than adult male patients with epilepsy. There were sex differences in the risk factors associated with depression among patients with epilepsy.

First report of powdery mildew on Euonymus japonicus caused by Erysiphe euonymicola in Taiwan.

The Japanese spindle (Euonymus japonicus Thunb.) is commonly used as an ornamental hedge plant in Taiwan. In March 2020, a severe powdery mildew disease was observed on E. japonicus surrounding a city park spanning six hectares in Taichung city, Taiwan. Around 90% of the plants showed symptoms on the leaves and pedicels of young shoots. Similar symptoms were observed in other districts of Taichung city and Taipei city between March to June in subsequent years. Initial signs of infection manifest as circular chlorotic spots on the leaves, which are subsequently covered by white mycelia on either the upper or lower surfaces of the spots. In severe cases, both sides of the leaves become entirely covered by dense mycelia. Hyphal appressoria were solitary or in opposite paired, lobed to multilobed. Conidiophores grow erectly from the hyphae, consist of 2-3 cylindrical cells, 38.9 to 78.6 × 6.31 to 8.28 µm (n = 30). Foot cells are usually straight or slightly flexuous, 23.6 to 43.2 µm (n = 30), followed by 1 to 2 shorter cells. Ellipsoidal conidia are produced singly on the conidiophores, 24.1 to 36.3 × 10.6 to 14.97 µm (n = 30), without fibrosin bodies. Germ tubes are mostly subterminal, sometimes terminal, occasionally exhibiting a longitudinal pattern. Chasmothecia were not observed. These morphological characteristics correspond to the description of Erysiphe euonymicola U. Braun (Braun and Cook 2012), one of the Erysiphe species reported on E. japonicus. Genomic DNA was extracted from seven isolates obtained from different plants in the affected regions. The internal transcribed spacer (ITS) and 28S large subunit (LSU) of rDNA sequences (ITS accession nos.: OR073423-OR073429; LSU accession nos.: OR073448-OR073454) were amplified and sequenced using primer sets PMITS-1 / PMITS-2 (Cunnington et al. 2003) and NLP2 / PRM2 (Bradshaw and Tobin 2020), respectively. The resulting sequences exhibited identities ranging from 99.1 to 100% in ITS and 100% in LSU when compared to the corresponding sequences of E. euonymicola MUMH 133 (ITS: AB250228; LSU: AB250230) (Limkaisang et al. 2006). Phylogenetic analysis based on the concatenated sequences of ITS and LSU clustered the seven isolates within the same clade as three E. euonymicola isolates (MUMH 133, MUMH 6999 and MUMH 7012). Pathogenicity assays were conducted on one-meter tall E. japonicus plants by gently smearing infected leaves on all leaves of four healthy plants. Four uninoculated plants were used as control. All eight assayed plants were enclosed in plastic bags to maintain high humidity at 28 ± 2°C for 3 days. Chlorotic spots began to appear on leaves younger than one month old at 7 days post inoculation (dpi). By 28 dpi, all inoculated plants showed symptoms. Spots expanded or merged and formed a dense mycelial layer on leaves younger than three months, while mature dark green leaves were asymptomatic. No symptoms were observed on any leaves of the control plants. The morphological characteristics and sequences of ITS and LSU of the pathogen from the inoculated plants matched the above information. Based on these findings, E. euonymicola was identified as the causal agent of powdery mildew on E. japonicus, representing the first documented report of this disease in Taiwan. A voucher specimen TNM F0037001 (isolate EPM-1) was deposited in the National Museum of Natural Science, Taiwan. The pathogen has been frequently reported in recent years and significantly impacts the ornamental value of Euonymus spp. (Abbasi and Braun 2020; Lee et al. 2015; Li et al. 2011; Pei et al. 2022). This report also provides an evidence of an ongoing outbreak of the pathogen.

Adenine nucleotide carrier protein dysfunction in human disease.

Adenine nucleotide translocase (ANT) is the prototypical member of the mitochondrial carrier protein family, primarily involved in ADP/ATP exchange across the inner mitochondrial membrane. Several carrier proteins evolutionarily related to ANT, including SLC25A24 and SLC25A25, are believed to promote the exchange of cytosolic ATP-Mg2+ with phosphate in the mitochondrial matrix. They allow a net accumulation of adenine nucleotides inside mitochondria, which is essential for mitochondrial biogenesis and cell growth. In the last two decades, mutations in the heart/muscle isoform 1 of ANT (ANT1) and the ATP-Mg2+ transporters have been found to cause a wide spectrum of human diseases by a recessive or dominant mechanism. Although loss-of-function recessive mutations cause a defect in oxidative phosphorylation and an increase in oxidative stress which drives the pathology, it is unclear how the dominant missense mutations in these proteins cause human diseases. In this review, we focus on how yeast was productively used as a model system for the understanding of these dominant diseases. We also describe the relationship between the structure and function of ANT and how this may relate to various pathologies. Particularly, mutations in Aac2, the yeast homolog of ANT, were recently found to clog the mitochondrial protein import pathway. This leads to mitochondrial precursor overaccumulation stress (mPOS), characterized by the toxic accumulation of unimported mitochondrial proteins in the cytosol. We anticipate that in coming years, yeast will continue to serve as a useful model system for the mechanistic understanding of mitochondrial protein import clogging and related pathologies in humans.

Mitochondrial protein import clogging as a mechanism of disease.

Mitochondrial biogenesis requires the import of >1,000 mitochondrial preproteins from the cytosol. Most studies on mitochondrial protein import are focused on the core import machinery. Whether and how the biophysical properties of substrate preproteins affect overall import efficiency is underexplored. Here, we show that protein traffic into mitochondria can be disrupted by amino acid substitutions in a single substrate preprotein. Pathogenic missense mutations in ADP/ATP translocase 1 (ANT1), and its yeast homolog ADP/ATP carrier 2 (Aac2), cause the protein to accumulate along the protein import pathway, thereby obstructing general protein translocation into mitochondria. This impairs mitochondrial respiration, cytosolic proteostasis, and cell viability independent of ANT1's nucleotide transport activity. The mutations act synergistically, as double mutant Aac2/ANT1 causes severe clogging primarily at the translocase of the outer membrane (TOM) complex. This confers extreme toxicity in yeast. In mice, expression of a super-clogger ANT1 variant led to neurodegeneration and an age-dependent dominant myopathy that phenocopy ANT1-induced human disease, suggesting clogging as a mechanism of disease. More broadly, this work implies the existence of uncharacterized amino acid requirements for mitochondrial carrier proteins to avoid clogging and subsequent disease.

Inside our cells, compartments known as mitochondria generate the chemical energy required for life processes to unfold. Most of the proteins found within mitochondria are manufactured in another part of the cell (known as the cytosol) and then imported with the help of specialist machinery. For example, the TOM and TIM22 channels provide a route for the proteins to cross the two membrane barriers that separate the cytosol from the inside of a mitochondrion. ANT1 is a protein that is found inside mitochondria in humans, where it acts as a transport system for the cell's energy currency. Specific mutations in the gene encoding ANT1 have been linked to degenerative conditions that affect the muscles and the brain. However, it remains unclear how these mutations cause disease. To address this question, Coyne et al. recreated some of the mutations in the gene encoding the yeast equivalent of ANT1 (known as Aac2). Experiments in yeast cells carrying these mutations showed that the Aac2 protein accumulated in the TOM and TIM22 channels, creating a 'clog' that prevented other essential proteins from reaching the mitochondria. As a result, the yeast cells died. Mutant forms of the human ANT1 protein also clogged up the TOM and TIM22 channels of human cells in a similar way. Further experiments focused on mice genetically engineered to produce a "super-clogger" version of the mouse equivalent of ANT1. The animals soon developed muscle and neurological conditions similar to those observed in human diseases associated with ANT1. The findings of Coyne et al. suggest that certain genetic mutations in the gene encoding the ANT1 protein cause disease by blocking the transport of other proteins to the mitochondria, rather than by directly affecting ANT1's nucleotide trnsport role in the cell. This redefines our understanding of diseases associated with mitochondrial proteins, potentially altering how treatments for these conditions are designed.

A Gravity-Fed Transcardial Perfusion Method for Histologic Analysis of the Mouse Central Nervous System.

The histologic analysis of brain and spinal cord specimens isolated from mice is common practice for the assessment of pathology in this model system. To maintain the morphology of these delicate tissues, it is routine to administer a chemical fixative such as paraformaldehyde via cannulation of the heart in anesthetized animals (transcardial perfusion). Transcardial perfusion of the mouse heart has traditionally relied on the use of peristaltic pumps or air pressure to deliver both the saline and fixative solutions necessary for this process. As an easily accessible alternative to these methods, this work demonstrates the use of a gravity-fed method of perfusate delivery that uses materials available in most hardware stores. To validate this new perfusion method, this work demonstrates all the subsequent steps necessary for the sensitive detection of phosphorylated α-synuclein in both the brain and spinal cord. Included in these steps are the dissection of the fixed brain and spinal cord tissues, rapid freezing/embedding and cryosectioning of the tissues, and immunofluorescent staining. As this method results in whole-body delivery of the fixative, it may also be used to prepare other non-neuronal tissues for histologic analysis.

Cytosolic adaptation to mitochondria-induced proteostatic stress causes progressive muscle wasting.

Mitochondrial dysfunction causes muscle wasting in many diseases and probably also during aging. The underlying mechanism is poorly understood. We generated transgenic mice with unbalanced mitochondrial protein loading and import, by moderately overexpressing the nuclear-encoded adenine nucleotide translocase, Ant1. We found that these mice progressively lose skeletal muscle. Ant1-overloading reduces mitochondrial respiration. Interestingly, it also induces small heat shock proteins and aggresome-like structures in the cytosol, suggesting increased proteostatic burden due to accumulation of unimported mitochondrial preproteins. The transcriptome of Ant1-transgenic muscles is drastically remodeled to counteract proteostatic stress, by repressing protein synthesis and promoting proteasomal function, autophagy, and lysosomal amplification. These proteostatic adaptations collectively reduce protein content thereby reducing myofiber size and muscle mass. Thus, muscle wasting can occur as a trade-off of adaptation to mitochondria-induced proteostatic stress. This finding could have implications for understanding the mechanism of muscle wasting, especially in diseases associated with Ant1 overexpression, including facioscapulohumeral dystrophy.

Potentially Overestimated Efficacy of Nanoparticle Albumin-bound Paclitaxel compared with Solvent-based Paclitaxel in Breast Cancer: A Systemic Review and Meta-analysis.

Background: Nanoparticle albumin-bound paclitaxel (nab-PTX) has exhibited clinical efficacy in breast cancer treatment, but toxicities can be yielded more at the same time. We did this meta-analysis aiming to unambiguously compare nab-PTX with conventional solvent-based paclitaxel (sb-PTX) in breast cancer patients of all stages. Method: Pubmed, Embase and Cochrane Library were searched for head-to-head randomized controlled trials of nab-PTX and sb-PTX in breast cancer. Risk ratio (RR) with 95% confidence interval was used for dichotomous variables while Hazard ratio (HR) was used for time-to-event outcomes. Results: Our review finally included 9 studies with 3508 patients. Nab-PTX showed a benefit on objective response rate (ORR) (RR=1.22 [1.04-1.43], P=0.01) as well as non-inferiority compared with sb-PTX in disease control rate (DCR) (RR=1.01 [0.98-1.04], P=0.44), overall survival (OS) (HR=0.99 [0.93-1.05], P=0.81) and disease free survival/progression free survival (DFS/PFS) (HR=0.92 [0.81-1.05], P=0.21). However, when it comes to toxicities (fatigue, nausea or vomiting, peripheral sensory neuropathy and adverse event related discontinuation), results favored sb-PTX (RR=2.89 [1.07-7.8], 3.15 [1.78-5.59], 2.11 [1.32-3.37], 2.02 [1.61-2.53]; P<0.05). Patients with metastatic tumors or undergoing conventional schedule responses better to nab-PTX than the compared groups (RR of ORR in metastatic vs early or locally advanced patients: 1.46 [1.09-1.96] vs 1.01 [0.94-1.08]; conventional vs dose dense group: 1.59 [1.23-2.06] vs 1.01 [0.91-1.12]). Conclusions: Nab-PTX can improve ORR compared with paclitaxel and should be given priority to when aiming to reduce tumor load in breast cancer. Sb-PTX of dose dense schedule is recommended when toxicity of nab-PTX is hard to bear for breast cancer patients.

Fourty-nine years old woman co-infected with SARS-CoV-2 and Mycoplasma: A case report.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new virus responsible for the outbreak of respiratory illness known as coronavirus disease 2019 (CoVID-19). Mycoplasma is an uncommon co-infected pathogen with SARS-CoV-2 and has not yet been reported. Computed tomography (CT), used as an accessory examination, may play a more significant role in this co-infection. CASE SUMMARY: A 49-year-old female presented with a cough, expectoration and chest congestion followed by elevated C-reactive protein and erythrocyte sedimentation rate. CT images showed ground-glass opacities in bilateral lower lobes and a patchy and striate shadow in the right upper lobe. Immunoglobulin M antibody of Mycoplasma pneumoniae was positive and real-time fluorescence polymerase chain reaction of sputum was positive for SARS-CoV-2 nucleic acid. The diagnosis of CoVID-19 was made based on laboratory results, chest CT images, clinical manifestations and epidemiologic characteristics. She was treated with combination therapy for 17 d and showed a marked reCoVery. CONCLUSION: Co-infection with SARS-CoV-2 and Mycoplasma in CoVID-19 patients appears to be uncommon. CT is an acceptable method for the primary diagnosis and treatment should be initiated as soon as possible. Combination therapy with antiviral, anti-inflammatory, traditional Chinese herbal medicine and interferon inhalation may be a reference for further progress in treating this co-infection.

Copper(i)-catalyzed intermolecular cyanoarylation of alkenes: convenient access to α-alkylated arylacetonitriles.

A novel Cu(i)-catalyzed intermolecular cyanoarylation of alkenes with diaryliodonium salts as a radical arylating reagent and tetra-butylammonium cyanide as an electrophilic cyanating reagent was established. A broad range of α-alkylated arylacetonitriles were efficiently constructed in good to excellent yields under base- and oxidant-free and mild conditions.

FLT3 inhibition upregulates HDAC8 via FOXO to inactivate p53 and promote maintenance of FLT3-ITD+ acute myeloid leukemia.

Internal tandem duplication (ITD) mutations within the FMS-like receptor tyrosine kinase-3 (FLT3) can be found in up to 25% to 30% of acute myeloid leukemia (AML) patients and confer a poor prognosis. Although FLT3 tyrosine kinase inhibitors (TKIs) have shown clinical responses, they cannot eliminate primitive FLT3-ITD+ AML cells, which are potential sources of relapse. Therefore, elucidating the mechanisms underlying FLT3-ITD+ AML maintenance and drug resistance is essential to develop novel effective treatment strategies. Here, we demonstrate that FLT3 inhibition induces histone deacetylase 8 (HDAC8) upregulation through FOXO1- and FOXO3-mediated transactivation in FLT3-ITD+ AML cells. Upregulated HDAC8 deacetylates and inactivates p53, leading to leukemia maintenance and drug resistance upon TKI treatment. Genetic or pharmacological inhibition of HDAC8 reactivates p53, abrogates leukemia maintenance, and significantly enhances TKI-mediated elimination of FLT3-ITD+ AML cells. Importantly, in FLT3-ITD+ AML patient-derived xenograft models, the combination of FLT3 TKI (AC220) and an HDAC8 inhibitor (22d) significantly inhibits leukemia progression and effectively reduces primitive FLT3-ITD+ AML cells. Moreover, we extend these findings to an AML subtype harboring another tyrosine kinase-activating mutation. In conclusion, our study demonstrates that HDAC8 upregulation is an important mechanism to resist TKIs and promote leukemia maintenance and suggests that combining HDAC8 inhibition with TKI treatment could be a promising strategy to treat FLT3-ITD+ AML and other tyrosine kinase mutation-harboring leukemias.

Repeatedly Intrinsic Self-Healing of Millimeter-Scale Wounds in Polymer through Rapid Volume Expansion Aided Host-Guest Interaction.

Implantable and wearable materials, which are usually used in/on a biological body, are mostly needed with biomimetic self-healing function. To enable repeatable large-wound self-healing and volume/structure recovery, we verified a proof-of-concept approach in this work. We design a polymer hydrogel that combines temperature responsiveness with an intrinsic self-healing ability through host-guest orthogonal self-assembly between two types of poly(N-isopropylacrylamide) (PNIPAM) oligomers. The result is thermosensitive, capable of fast self-repair of microcracks based on reversible host-guest assembly. More importantly, when a large open wound appears, the hydrogel can first close the wound via volume swelling and then completely self-repair the damage in terms of intrinsic self-healing. Meanwhile, its original volume can be easily recovered by subsequent contraction. As demonstrated by the experimental data, such millimeter-level wound self-healing and volume recovery can be repeatedly carried out in response to the short-term cooling stimulus. With low cytotoxicity and good biocompatibility, moreover, this highly intelligent hydrogel is greatly promising for practical large-wound self-healing in wound dressing, electronic skins, wearable biosensors, and humanoid robotics, which can tolerate large-scale human motions.

Identification of a t(X;17)(q28;q21) generating a KANSL1-MTCP1 gene fusion leading to dysregulated expression of MTCP1 in acute myeloid leukemia.

Chromosomal translocations and generating fusion genes are closely associated with disease initiation and progression in acute myeloid leukemia (AML). In this study, we identified a novel t(X;17)(q28;q21) chromosomal rearrangement in a patient with acute monocytic leukemia. Using RNA-sequencing, we identified a KANSL1-MTCP1 and a KANSL1-CMC4 fusion gene. 5'-UTR sequences of the KANSL1 gene were found to become fused upstream of the coding sequence region of the MTCP1 and CMC4 genes, respectively, resulting in an aberrantly high expression of these genes. Functional studies revealed that overexpression of the MTCP1 gene induced an increased cell proliferation and partial blockage of cell differentiation, suggesting that the aberrant expression of MTCP1 is of critical importance in leukemogenesis.

Consequences of inner mitochondrial membrane protein misfolding.

Proteins embedded in the inner mitochondrial membrane (IMM) perform essential cellular functions. Maintaining the folding state of these proteins is therefore of the utmost importance, and this is ensured by IMM chaperones and proteases that refold and degrade unassembled and misfolded proteins. However, the physiological consequences specific to IMM protein misfolding remain obscure because deletion of these chaperones/proteases (the typical experimental strategy) often affects many mitochondrial processes other than protein folding and turnover. Thus, novel experimental systems are needed to evaluate the direct effects of misfolded protein on the membrane. Such a system has been developed in recent years. Studies suggest that numerous pathogenic mutations in isoform 1 of adenine nucleotide translocase (Ant1) cause its misfolding on the IMM. In this review, we first discuss potential mechanisms by which dominant Ant1 mutations may cause disease, highlighting IMM protein misfolding, per se, as a likely pathological factor. Then we discuss the intramitochondrial effects of Ant1 misfolding such as IMM proteostatic stress, respiratory chain dysfunction, and mtDNA instability. Finally, we summarize the mounting evidence that IMM proteostatic stress can perturb mitochondrial protein import to cause the toxic accumulation of mitochondrial proteins in the cytosol: a cell stress mechanism termed mitochondrial Precursor Overaccumulation Stress (mPOS).

Mitochondrial carrier protein overloading and misfolding induce aggresomes and proteostatic adaptations in the cytosol.

Previous studies in yeast showed that mitochondrial stressors not directly targeting the protein import machinery can cause mitochondrial precursor overaccumulation stress (mPOS) in the cytosol independent of bioenergetics. Here, we demonstrate mPOS and stress responses in human cells. We show that overloading of mitochondrial membrane carrier, but not matrix proteins, is sufficient to induce cytosolic aggresomes and apoptosis. The aggresomes appear to triage unimported mitochondrial proteins. Interestingly, expression of highly unstable mutant variants of the mitochondrial carrier protein, Ant1, also induces aggresomes despite a greater than 20-fold reduction in protein level compared to wild type. Thus, overloading of the protein import machinery, rather than protein accumulation, is critical for aggresome induction. The data suggest that the import of mitochondrial proteins is saturable and that the cytosol is limited in degrading unimported mitochondrial proteins. In addition, we found that EGR1, eEF1a, and ubiquitin C are up-regulated by Ant1 overloading. These proteins are known to promote autophagy, protein targeting to aggresomes, and the processing of protein aggregates, respectively. Finally, we found that overexpression of the misfolded variants of Ant1 induces additional cytosolic responses including proteasomal activation. In summary, our work captured a profound effect of unimported mitochondrial proteins on cytosolic proteostasis and revealed multiple anti-mPOS mechanisms in human cells.

[Effect of Amino Acid Motifs in Integrin ß3 Cytoplasmic Tail on αâ ¡bß3-Mediated Cell function in 293T cell models].

OBJECTIVE: To establish 293T cell lines stably expressing Calpain-cleavage related α3 cytoplasmic tail mutants, and to explore the effect of amino acid motifs in integrin ß3 cytoplasmic tail on αⅡbß3-mediated cell function. METHODS: 293T cell lines stably co-expressing human wild type integrin αⅡb and full length ß3 or mutant ß3, including ß3-ΔNITY (ß3 cytoplasmic tail NITY motif deleted), ß3-Δ754 (ß3 cytoplasmic tail TNITYRGT motif deleted) and ß3-Δ759 (ß3 cytoplasmic tail RGT motif deleted) were established. Spreading and adhesion of these stable cell lines on immobilized fibrinogen were tested. RESULTS: 293T-αⅡbß3ΔNITY, 293T-αⅡbß3Δ754, 293T-αⅡbß3Δ759 and 293T-αⅡbß3 cell lines were successfully established. Compared with the 293T cells, 293T-αⅡbß3 cells which expressed full ß3, possessed well adhesion and spread ability on immobilized fibrinogen, suggesting it can be as a surrogate for platelet. Compared with 293T-αⅡbß3 cells, the 293T-αⅡbß3ΔNITY cells showed a partial impairment of adhesion and spreadability on immobilized fibrinogen. while the 293T-αⅡbß3Δ754 cells and 293T-αⅡbß3Δ759 cells failed to adhere or spread on immobilized fibrinogen. CONCLUSION: To the cell spreading function mediated by integrin ß3, RGT motif is vital, while NITY can be dispensable. These established 293T cell lines stably expressing different ß3 mutants provide a solid basis for a further analysis of mass spectrometry.

Homoharringtonine deregulates MYC transcriptional expression by directly binding NF-κB repressing factor.

Homoharringtonine (HHT), a known protein synthesis inhibitor, has an anti-myeloid leukemia effect and potentiates the therapeutic efficacy of anthracycline/cytarabine induction regimens for acute myelogenous leukemia (AML) with favorable and intermediate prognoses, especially in the t(8;21) subtype. Here we provide evidence showing that HHT inhibits the activity of leukemia-initiating cells (Lin-/Sca-1-/c-kit+; LICs) in a t(8;21) murine leukemia model and exerts a down-regulating effect on MYC pathway genes in human t(8;21) leukemia cells (Kasumi-1). We discovered that NF-κB repressing factor (NKRF) is bound directly by HHT via the second double-strand RNA-binding motif (DSRM2) domain, which is the nuclear localization signal of NKRF. A series of deletion and mutagenesis experiments mapped HHT direct binding sites to K479 and C480 amino acids in the DSRM2 domain. HHT treatment shifts NKRF from the nucleus (including nucleoli) to the cytoplasm by occupying the DSRM2 domain, strengthens the p65-NKRF interaction, and interferes with p65-p50 complex formation, thereby attenuating the transactivation activity of p65 on the MYC gene. Moreover, HHT significantly decreases the expression of KIT, a frequently mutated and/or highly expressed gene in t(8;21) AML, in concert with MYC down-regulation. Our work thus identifies a mechanism of action of HHT that is different from, but acts in concert with, the known mode of action of this compound. These results justify further clinical testing of HHT in AML.

Mitochondria-cytosol-nucleus crosstalk: learning from Saccharomyces cerevisiae.

Mitochondria are key cell organelles with a prominent role in both energetic metabolism and the maintenance of cellular homeostasis. Since mitochondria harbor their own genome, which encodes a limited number of proteins critical for oxidative phosphorylation and protein translation, their function and biogenesis strictly depend upon nuclear control. The yeast Saccharomyces cerevisiae has been a unique model for understanding mitochondrial DNA organization and inheritance as well as for deciphering the process of assembly of mitochondrial components. In the last three decades, yeast also provided a powerful tool for unveiling the communication network that coordinates the functions of the nucleus, the cytosol and mitochondria. This crosstalk regulates how cells respond to extra- and intracellular changes either to maintain cellular homeostasis or to activate cell death. This review is focused on the key pathways that mediate nucleus-cytosol-mitochondria communications through both transcriptional regulation and proteostatic signaling. We aim to highlight yeast that likely continues to serve as a productive model organism for mitochondrial research in the years to come.

Heme oxygenase-1 participates in the resolution of seawater drowning-induced acute respiratory distress syndrome.

The aim of the present study was to investigate whether heme oxygenase-1(HO-1) participated in the resolution of seawater drowning-induced acute respiratory distress syndrome (ARDS). In this study, gross and microscopic morphology of pulmonary tissue, computed tomography images and biochemical indexes were continuously observed from 15min to 15day after seawater drowning. The content and activity of HO-1 were determined by western-blot and spectrophotometric method, respectively. The morphological and biochemical indexes indicated that the seawater drowning could lead to the serious pulmonary hemorrhage and edema. However, 6h after drowning, these morphological and biochemical indexes gradually returned to basal level. Meanwhile, seawater drowning increased the HO-1 expression and activity while Zinc protoporphyrin (a HO-1 specific activity inhibitor) decreased the content of transforming growth factor beta-1 in lung tissue and hampered the repair process of seawater drowning-induced ARDS. Thus, HO-1 participates in the resolution of seawater drowning-induced ARDS.