Mussel-inspired chitosan and its applications in the biomedical field.

Chitosan (CS) has physicochemical properties including solubility, crystallinity, swellability, viscosity, and cohesion, along with biological properties like biocompatibility, biodegradation, antioxidant, antibacterial, and antitumor effects. However, these characteristics of CS are greatly affected by its degree of deacetylation, molecular weight, pH and other factors, which limits the application of CS in biomedicine. The modification of CS with catechol-containing substances inspired by mussels can not only improve these properties of CS, but also endow it with self-healing property, providing an environmentally friendly and sustainable way to promote the application of CS in biomedicine. In this paper, the properties of CS and its limitation in the biomedical filed are introduced in detail. Then, the modification methods and properties of substances with catechol groups inspired by mussels on CS are reviewed. Finally, the applications of modified CS in the biomedical field of wound healing, drug delivery, anticancer therapy, biosensor and 3D printing are further discussed. This review can provide valuable information for the design and exploitation of mussel-inspired CS in the biomedical field.

Noninvasive prediction of CCL2 expression level in high-grade glioma patients.

BACKGROUND: Gliomas are recognized as the most frequent type of malignancies in the central nervous system, and efficacious prognostic indicators are essential to treat patients with gliomas and improve their clinical outcomes. The chemokine (C-C motif) ligand 2 (CCL2) is a promising predictor for glioma malignancy and progression. However, at present, the methods to evaluate CCL2 expression level are invasive and operator-dependent. OBJECTIVE: It was expected to noninvasively predict CCL2 expression levels in malignant glioma tissues by magnetic resonance imaging (MRI)-based radiomics and assess the association between the developed radiomics model and prognostic indicators and related genes. METHODS: MRI-based radiomics was used to predict CCL2 expression level using data obtained from The Cancer Imaging Archive (TCIA) and The Cancer Genome Atlas (TCGA) databases. A support vector machine (SVM)-based radiomics model and a logistic regression (LR)-based radiomics model were used to predict the radiomics score, and its correlation with CCL2 expression level was analyzed. RESULTS: The results revealed that there was an association between CCL2 expression level and the overall survival of cases with gliomas, and bioinformatics correlation analysis showed that CCL2 expression level was highly correlated with disease-related pathways, such as mTOR signaling pathway, cGMP-PKG signaling pathway, and MAPK signaling pathway. Both SVM- and LR-based radiomics data robustly predicted CCL2 expression level, and radiomics scores could also be used to predict the overall survival of patients. Moreover, the high/low radiomics scores were highly correlated with the known glioma-related genes, including CD70, CD27, and PDCD1. CONCLUSION: An MRI-based radiomics model was successfully developed, and its clinical benefits were confirmed, including the prediction of CCL2 expression level and patients' prognosis.

Associations between CDH1 gene polymorphisms and the risk of gastric cancer: A meta-analysis based on 44 studies.

BACKGROUND: Numerous studies have investigated the association between CDH1 polymorphisms and gastric cancer (GC) risk. However, the results have been inconsistent and controversial. To further determine whether CDH1 polymorphisms increase the risk of GC, we conducted a meta-analysis by pooling the data. METHODS: Relevant case-control studies were collected from PubMed, Embase, Web of Science and Cochrane databases up to January 7, 2024. Subsequently, odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of correlations. A sensitivity analysis was performed to evaluate the robustness and reliability of these included studies. RESULTS: A total of 25 articles including 44 studies, were included in this meta-analysis, including 26 studies on rs16260, 6 studies on rs3743674, 7 studies on rs5030625, and 5 studies on rs1801552. The pooled results showed that rs16260 was remarkably associated with an increased GC risk of GC among Caucasians. Moreover, the rs5030625 variation dramatically enhanced GC predisposition in the Asian population. However, no evident correlations between CDH1 rs3743674 and rs1801552 polymorphisms and GC risk were observed. CONCLUSIONS: Our findings suggested that CDH1 gene polymorphisms were significantly correlated with GC risk, especially in rs16260 and rs5030625 polymorphisms.

Effects of Abaloparatide on Bone Mineral Density in Proximal Femoral Regions Corresponding to Arthroplasty Gruen Zones: A Study of Postmenopausal Women with Osteoporosis.

BACKGROUND: Low hip bone mineral density (BMD) in patients who undergo total hip arthroplasty (THA) increases the risk of periprosthetic fractures, implant instability, and other complications. Recently, emphasis has been placed on bone health optimization: treating low BMD prior to a planned orthopaedic implant procedure in an effort to normalize BMD and reduce the potential risk of future complications. Abaloparatide is a U.S. Food and Drug Administration-approved osteoanabolic agent for men and postmenopausal women with osteoporosis and a candidate drug for bone health optimization that, in addition to benefits at the spine, increases hip BMD and reduces nonvertebral fracture risk. We hypothesized that abaloparatide would improve BMD in proximal femoral regions surrounding a virtual THA stem. METHODS: This post hoc analysis obtained dual x-ray absorptiometry (DXA) hip scans from 500 randomly selected postmenopausal women with osteoporosis from the Phase-3 Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE, NCT01343004) study after 0, 6, and 18 months of abaloparatide (250 patients) or placebo (250 patients). Hip DXA scans underwent 3-dimensional (3D) modeling via 3D-Shaper, followed by virtual resection of the proximal femur and simulated placement of a tapered, flat-wedge hip stem that guided delineation of the Gruen zones that were fully (zones 1 and 7) or largely (zones 2 and 6) captured in the scanning region. Integral, cortical, and trabecular volumetric BMD, cortical thickness, and cortical surface BMD (the product of cortical volumetric BMD and cortical thickness) were determined for each zone. RESULTS: Compared with placebo, the abaloparatide group showed greater increases in integral volumetric BMD in all zones at months 6 and 18; cortical surface BMD in zones 1, 6, and 7 at month 6; cortical thickness, cortical volumetric BMD, and cortical surface BMD in all zones at month 18; and trabecular volumetric BMD in zones 1 and 7 at months 6 and 18. CONCLUSIONS: Abaloparatide increases BMD in proximal femoral regions that interact with and support femoral stems, suggesting that abaloparatide may have value for preoperative or potentially perioperative bone health optimization in patients with osteoporosis undergoing THA. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Treatment patterns in women with postmenopausal osteoporosis using abaloparatide: a real-world observational study.

Review of medical records from 173 women with osteoporosis who received abaloparatide treatment revealed that 96.0% had at least one visit for osteoporosis management and 55.5% had medication support group access. The most common reasons for discontinuing treatment were financial (31.2%) and tolerability (22.8%). Most patients (64.8%) completed treatment as prescribed. PURPOSE: Abaloparatide is approved for the treatment of women with postmenopausal osteoporosis at high risk for fracture. This study evaluated real-world treatment patterns for patients new to abaloparatide, regardless of osteoporosis treatment history. METHODS: Data for patients with ≥ 1 prescription for abaloparatide were collected retrospectively from six academic and clinical practice settings across the US. RESULTS: A total of 173 patients were enrolled (mean [SD] age, 69.8 [7.4] years). At the time of abaloparatide treatment initiation, 78.6% had received other osteoporosis medications. Mean (SD) time from discontinuation of osteoporosis medications prior to initiation of abaloparatide was 1.7 (3.2) years. Twenty-four months of follow-up data from the initiation date of abaloparatide was collected from 94.0% of patients and 6.0% of patients had 12-24 months of follow-up. During the follow-up period, 96.0% of patients had at least one visit for osteoporosis management and 55.5% had access to a medication support program. The median duration of therapy was 18.6 months and 105/162 (64.8%) completed abaloparatide treatment as prescribed. The most common reasons for treatment discontinuation were financial (31.2%) and tolerability (22.8%). Following completion of a course of treatment with abaloparatide, 82/162 (50.6%) patients transitioned to another osteoporosis medication. The median time between abaloparatide treatment course completion and the initiation of follow-on medication was 21 days. CONCLUSION: Most patients completed treatment with abaloparatide as prescribed, and over half continued with an antiresorptive agent. This favorable conduct may be the result of regular follow-up visits and accessibility to both medication and patient support services.

Assembly of Glycopeptides in Living Cells Resembling Viral Infection for Cargo Delivery.

Self-assembly in living cells represents one versatile strategy for drug delivery; however, it suffers from the limited precision and efficiency. Inspired by viral traits, we here report a cascade targeting-hydrolysis-transformation (THT) assembly of glycosylated peptides in living cells holistically resembling viral infection for efficient cargo delivery and combined tumor therapy. We design a glycosylated peptide via incorporating a ß-galactose-serine residue into bola-amphiphilic sequences. Co-assembling of the glycosylated peptide with two counterparts containing irinotecan (IRI) or ligand TSFAEYWNLLSP (PMI) results in formation of the glycosylated co-assemblies SgVEIP, which target cancer cells via ß-galactose-galectin-1 association and undergo galactosidase-induced morphological transformation. While GSH-reduction causes release of IRI from the co-assemblies, the PMI moieties release p53 and facilitate cell death via binding with protein MDM2. Cellular experiments show membrane targeting, endo-/lysosome-mediated internalization and in situ formation of nanofibers in cytoplasm by SgVEIP. This cascade THT process enables efficient delivery of IRI and PMI into cancer cells secreting Gal-1 and overexpressing ß-galactosidase. In vivo studies illustrate enhanced tumor accumulation and retention of the glycosylated co-assemblies, thereby suppressing tumor growth. Our findings demonstrate an in situ assembly strategy mimicking viral infection, thus providing a new route for drug delivery and cancer therapy in the future.

Real-World Evidence to Support the Registration of a New Osteoporosis Medicinal Product in Europe.

Real-World Evidence (RWE), which has historically been used to support post-approval safety studies, has recently gained acceptance for new drug applications as supportive evidence or as new clinical evidence for medicinal products with orphan designation and/or in disease areas with high unmet need. Here, we present a case study for the use of RWE in the approval of abaloparatide in the European Union (EU) under the tradename Eladynos. In addition to data from the pivotal Phase 3 study, the marketing authorization application (MAA) included clinical data from additional interventional and observational studies, as well as post-marketing data obtained from the United States (US) market since approval of abaloparatide by the Food and Drug Administration (FDA) in 2017. The new interventional studies were not designed to assess fracture efficacy and cardiovascular safety which were topics of concern raised by the Committee for Medicinal Products for Human Use (CHMP) during their review of the initial MAA submitted in 2015. However, these studies taken together with the RWE formed the basis for a new MAA. Prior to the planned resubmission in the EU, national Scientific Advice (SA) was sought on the proposed clinical program, specifically on the relevance of Real-World Data (RWD) derived from an observational study to support and complement the efficacy and safety data already available from prospective randomized clinical trials. This case study demonstrates successful use of RWE to address a previously identified gap raised by the CHMP during the review of an earlier MAA, which led to the approval of Eladynos for the treatment of osteoporosis in the EU.

Targeted macrophage phagocytosis by Irg1/itaconate axis improves the prognosis of intracerebral hemorrhagic stroke and peritonitis.

BACKGROUND: Macrophages are innate immune cells whose phagocytosis function is critical to the prognosis of stroke and peritonitis. cis-aconitic decarboxylase immune-responsive gene 1 (Irg1) and its metabolic product itaconate inhibit bacterial infection, intracellular viral replication, and inflammation in macrophages. Here we explore whether itaconate regulates phagocytosis. METHODS: Phagocytosis of macrophages was investigated by time-lapse video recording, flow cytometry, and immunofluorescence staining in macrophage/microglia cultures isolated from mouse tissue. Unbiased RNA-sequencing and ChIP-sequencing assays were used to explore the underlying mechanisms. The effects of Irg1/itaconate axis on the prognosis of intracerebral hemorrhagic stroke (ICH) and peritonitis was observed in transgenic (Irg1flox/flox; Cx3cr1creERT/+, cKO) mice or control mice in vivo. FINDINGS: In a mouse model of ICH, depletion of Irg1 in macrophage/microglia decreased its phagocytosis of erythrocytes, thereby exacerbating outcomes (n = 10 animals/group, p < 0.05). Administration of sodium itaconate/4-octyl itaconate (4-OI) promoted macrophage phagocytosis (n = 7 animals/group, p < 0.05). In addition, in a mouse model of peritonitis, Irg1 deficiency in macrophages also inhibited phagocytosis of Staphylococcus aureus (n = 5 animals/group, p < 0.05) and aggravated outcomes (n = 9 animals/group, p < 0.05). Mechanistically, 4-OI alkylated cysteine 155 on the Kelch-like ECH-associated protein 1 (Keap1), consequent in nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and transcriptional activation of Cd36 gene. Blocking the function of CD36 completely abolished the phagocytosis-promoting effects of Irg1/itaconate axis in vitro and in vivo. INTERPRETATION: Our findings provide a potential therapeutic target for phagocytosis-deficiency disorders, supporting further development towards clinical application for the benefit of stroke and peritonitis patients. FUNDING: The National Natural Science Foundation of China (32070735, 82371321 to Q. Li, 82271240 to F. Yang) and the Beijing Natural Science Foundation Program and Scientific Research Key Program of Beijing Municipal Commission of Education (KZ202010025033 to Q. Li).

Comparison of the cost-effectiveness of sequential treatment with abaloparatide in US men and women at very high risk of fractures.

BACKGROUND: Osteoporotic-related fractures represent an increasing burden to patients, health care systems and society. AIMS: This study estimated cost-effectiveness of sequential treatment with abaloparatide (ABL) followed by alendronate (ALN) compared to relevant alternative strategies in US men and women aged 50 to 80 years at very high fracture risk (bone mineral density T-score ≤ - 2.5 and a recent fracture). METHODS: A lifetime Markov-based microsimulation model was used to estimate healthcare costs and quality-adjusted life years (QALYs). Comparators were sequential treatment with unbranded teriparatide (TPTD)/ALN, generic ALN monotherapy, and no treatment. Analyses were conducted based on initial fracture site (hip, vertebral, or any fracture) and treatment efficacy data (derived from clinical trials or a recent network meta-analysis). RESULTS: From all analyses completed, sequential ABL/ALN demonstrated more QALYs for lower healthcare costs versus unbranded TPTD/ALN. No treatment was dominated (higher costs for less QALYs) versus ALN monotherapy. Sequential ABL/ALN resulted in favorable cost-effectiveness (at US threshold of $150,000/QALY) versus generic ALN monotherapy in men aged ≥ 50 years with any fracture type, women aged ≥ 65 years with any fracture type, and women aged ≥ 55 years having a hip or vertebral fracture. DISCUSSION: Similar cost-effectiveness of sequential ABL/ALN versus unbranded TPTD/ALN, ALN monotherapy, and no treatment was observed in both US men and women at very high fracture risk, with a moderate improvement in cost-effectiveness in men versus women and in patients with a hip or vertebral fracture. CONCLUSIONS: Sequential therapy with ABL/ALN was cost-effective in US men and women at very high risk of fractures.

Identification of telomere-associated gene signatures to predict prognosis and drug sensitivity in glioma.

OBJECTIVE: Gliomas are a heterogeneous group of brain tumors with distinct biological and clinical properties, leading to significant mortality and morbidity. Emerging evidence shows telomere maintenance has implicated in glioma susceptibility and prognosis. In this study, we comprehensively analyzed gene signatures related to telomere maintenance in glioma and their predictive values for predicting the prognosis and drug sensitivity in glioma. METHODS: We initially identified telomere-related genes differentially expressed between low-grade glioma (LGG) and glioblastoma (GBM) and accordingly developed a risk model by univariate and multivariate Cox analysis to assess the expressions of telomere-related genes across the risk groups. Finally, to assess these genes in immune function the anti-tumor medications often used in the clinical treatment of glioma, we computed immune cell infiltration analysis and drug sensitivity analysis. RESULTS: The consensus clustering analysis identified 20 telomere-related genes which split LGG patients into two distinct subtypes. The patient survival, the expressions of key telomere-related DEGs, and immune cell infiltration significantly differed between Cluster 1 and Cluster 2. The LASSO risk model [riskScore=(0.086)*HOXA7+(0.242)*WEE1+(0.247)*IGF2BP3+(0.052)*DUSP10] showed significant differences regarding the 1-, 3-, 5-year overall survival, immune cell infiltration, and drug sensitivity between high- and low-risk groups. The predictive nomogram constructed to quantify the survival probability of each sample at 1, 3, and 5 years was consistent with the actual patient survival. CONCLUSION: Our comprehensive characterization of telomere-associated gene signatures in glioma reveals their possible roles in the development, tumor microenvironment, and prognosis. The study provides some suggestive relationships between four telomere-related genes (HOXA7, WEE1, IGF2BP3, and DUSP10) and glioma prognosis.

Headspace solid-phase microextraction comprehensive 2D gas chromatography-time of flight mass spectrometry (HS-SPME-GC × GC-TOFMS) for origin traceability of the genus Hymenaea resinites.

Differentiating the chemical compositions of resinite (amber, copal, and resin) is very crucial for determining the botanical origin and chemical compositions of the fossilised amber and copal. This differentiation also assists in understanding the ecological functions of resinite. Headspace solid-phase microextraction-comprehensive two-dimensional (2D) gas chromatography-time-of-flight mass-spectroscopy (HS-SPME-GC × GC-TOFMS) was firstly proposed and utilised in this research to investigate the chemical components (volatile and semi-volatile compositions) and structures of Dominican amber, Mexican amber, and Colombian copal for origin traceability, which were all produced by trees belonging to the genus Hymenaea. Principal component analysis (PCA) was used to analyse the relative abundances of each compound. Several informative variables were selected, such as caryophyllene oxide, which was only found in Dominican amber, and copaene, which was only found in Colombian copal. 1H-Indene, 2,3-dihydro-1,1,5,6-tetramethyl- and 1,1,4,5,6-pentamethyl-2,3-dihydro-1H-indene were abundantly present in Mexican amber, which were the critical fingerprints for the origin traceability of amber and copal produced by trees from the genus Hymenaea of various geological places. Meanwhile, some characteristic compounds were closely related to the invasion of fungi and insects; their links with ancient fungi and insect categories were also decoded in this study and these special compounds could be used to further study the plant-insect interactions.

Bone Health Management in Elective Orthopaedic Surgery: A Claims-Based Observational Study.

Introduction: There are limited data on the management of bone health, including bone mineral density (BMD) evaluation and osteoporosis (OP) treatment, in patients undergoing elective orthopaedic surgeries. Methods: This was a retrospective cohort study using administrative claims data from Symphony Health, PatientSource for patients aged ≥50 years with documented kyphoplasty/vertebroplasty (KP/VP), total knee arthroplasty (TKA), and total hip arthroplasty (THA). Risk stratification to identify patients at very high risk for fracture (VHRFx) was based on clinical practice guideline recommendations to the extent information on variables of interest were available from the claims database. Results: A total of 251 919 patients met inclusion criteria: KP/VP (31 018), TKA (149 849), and THA (71 052). The majority were female (80.3%) with a mean (SD) age of 68.5 (7.5) years. Patients undergoing KP/VP were older and had a greater comorbidity burden associated with risk for falls, mobility issues, muscle weakness, and respiratory and cardiovascular diseases. In the 6 months before surgery, 11.8% of patients were tested and/or received treatment for OP. Patients undergoing KP/VP were more likely to be tested and/or treated (17.5%) than patients undergoing TKA (11.0%) or THA (10.9%). Overall, men had a lower rate of testing and/or treatment than women (4.6% vs 13.5%). In the 12 months before surgery, patients with an OP diagnosis and at VHRFx (30.8%) had a higher rate of treatment and/or testing than those without OP (11.5%), or those without OP but with a fracture in the year preceding surgery (10.2%). Conclusions: Bone health management is suboptimal in patients undergoing elective orthopaedic surgeries and is worse in men than in women. Proper management of OP before and after surgery may improve outcomes.

Aspergillus fumigatus Elongator complex subunit 3 affects hyphal growth, adhesion and virulence through wobble uridine tRNA modification.

The eukaryotic multisubunit Elongator complex has been shown to perform multiple functions in transcriptional elongation, histone acetylation and tRNA modification. However, the Elongator complex plays different roles in different organisms, and the underlying mechanisms remain unexplored. Moreover, the biological functions of the Elongator complex in human fungal pathogens remain unknown. In this study, we verified that the Elongator complex of the opportunistic fungal pathogen Aspergillus fumigatus consists of six subunits (Elp1-6), and the loss of any subunit results in similarly defective colony phenotypes with impaired hyphal growth and reduced conidiation. The catalytic subunit-Elp3 of the Elongator complex includes a S-adenosyl methionine binding (rSAM) domain and a lysine acetyltransferase (KAT) domain, and it plays key roles in the hyphal growth, biofilm-associated exopolysaccharide galactosaminogalactan (GAG) production, adhesion and virulence of A. fumigatus; however, Elp3 does not affect H3K14 acetylation levels in vivo. LC-MS/MS chromatograms revealed that loss of Elp3 abolished the 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) modification of tRNA wobble uridine (U34), and the overexpression of tRNAGlnUUG and tRNAGluUUC, which normally harbor mcm5s2U modifications, mainly rescues the defects of the Δelp3 mutant, suggesting that tRNA modification rather than lysine acetyltransferase is responsible for the primary function of Elp3 in A. fumigatus. Strikingly, global proteomic comparison analyses showed significantly upregulated expression of genes related to amino acid metabolism in the Δelp3 mutant strain compared to the wild-type strain. Western blotting showed that deletion of elp3 resulted in overexpression of the amino acid starvation-responsive transcription factor CpcA, and deletion of CpcA markedly reversed the defective phenotypes of the Δelp3 mutant, including attenuated virulence. Therefore, the findings of this study demonstrate that A. fumigatus Elp3 functions as a tRNA-modifying enzyme in the regulation of growth, GAG production, adhesion and virulence by maintaining intracellular amino acid homeostasis. More broadly, our study highlights the importance of U34 tRNA modification in regulating cellular metabolic states and virulence traits of fungal pathogens.

LASS2 overexpression enhances early apoptosis of lung cancer cells through the caspase­dependent pathway.

In a previous study by the authors, the longevity assurance homolog 2 (LASS2) gene was determined to inhibit activity of vacuolar H+­ATPase (V­ATPase) by combining with the C subunit (ATP6L) of V­ATPase. However, the influence of LASS2 overexpression and silencing on apoptosis of human lung cancer cells 95D or 95C remains unclear. Thus, the effect of LASS2 on apoptosis and its potential mechanisms were investigated in 95D and 95C cells. Using the lentiviral transfection method, lentiviral vectors of LASS2 overexpression and silencing were transfected into 95D and 95C cells, respectively. The apoptotic ability of tumor cells was observed by flow cytometry. The expression levels of LASS2, Bcl­2, Bax, cytochrome c, caspase­9, and caspase­3 were detected by western blotting. CCK­8 assay was used to detect the growth ability of tumor cells in vitro. Flow cytometric analysis revealed that LASS2 overexpression could promote the early apoptosis of lung cancer cells 95D. CCK­8 assay demonstrated that LASS2 overexpression inhibited the proliferation of 95D cells. Additionally, LASS2 overexpression decreased the expression of Bcl­2, induced the release of cytochrome c from mitochondria, and promoted the activation of caspase­9 and caspase­3. There was a significant difference in the expression of Bcl­2, cytochrome c, caspase­9 and caspase­3 in the LASS2­overexpression group compared with the normal and negative control groups. Alternatively, the aforementioned experiments in lung cancer cells 95C following LASS2 silencing produced the opposite effects. LASS2 may induce early apoptosis of lung cancer cells by influencing the caspase­dependent mitochondrial pathway.

Ubiquitination of CLIP-170 family protein restrains polarized growth upon DNA replication stress.

Microtubules play a crucial role during the establishment and maintenance of cell polarity. In fission yeast cells, the microtubule plus-end tracking proteins (+TIPs) (including the CLIP-170 homologue Tip1) regulate microtubule dynamics and also transport polarity factors to the cell cortex. Here, we show that the E3 ubiquitin ligase Dma1 plays an unexpected role in controlling polarized growth through ubiquitinating Tip1. Dma1 colocalizes with Tip1 to cortical sites at cell ends, and is required for ubiquitination of Tip1. Although the absence of dma1+ does not cause apparent polar growth defects in vegetatively growing cells, Dma1-mediated Tip1 ubiquitination is required to restrain polar growth upon DNA replication stress. This mechanism is distinct from the previously recognized calcineurin-dependent inhibition of polarized growth. In this work, we establish a link between Dma1-mediated Tip1 ubiquitination and DNA replication or DNA damage checkpoint-dependent inhibition of polarized growth in fission yeast.

Recovery from spindle checkpoint-mediated arrest requires a novel Dnt1-dependent APC/C activation mechanism.

The activated spindle assembly checkpoint (SAC) potently inhibits the anaphase-promoting complex/cyclosome (APC/C) to ensure accurate chromosome segregation at anaphase. Early studies have recognized that the SAC should be silenced within minutes to enable rapid APC/C activation and synchronous segregation of chromosomes once all kinetochores are properly attached, but the underlying silencers are still being elucidated. Here, we report that the timely silencing of SAC in fission yeast requires dnt1+, which causes severe thiabendazole (TBZ) sensitivity and increased rate of lagging chromosomes when deleted. The absence of Dnt1 results in prolonged inhibitory binding of mitotic checkpoint complex (MCC) to APC/C and attenuated protein levels of Slp1Cdc20, consequently slows the degradation of cyclin B and securin, and eventually delays anaphase entry in cells released from SAC activation. Interestingly, Dnt1 physically associates with APC/C upon SAC activation. We propose that this association may fend off excessive and prolonged MCC binding to APC/C and help to maintain Slp1Cdc20 stability. This may allow a subset of APC/C to retain activity, which ensures rapid anaphase onset and mitotic exit once SAC is inactivated. Therefore, our study uncovered a new player in dictating the timing and efficacy of APC/C activation, which is actively required for maintaining cell viability upon recovery from the inhibition of APC/C by spindle checkpoint.

Synergistic Antifungal Effect of a Combination of Iron Deficiency and Calcium Supplementation.

Fungal diseases have become a major public health issue worldwide. Increasing drug resistance and the limited number of available antifungals result in high morbidity and mortality. Metal-based drugs have been reported to be therapeutic agents against major protozoan diseases, but knowledge of their ability to function as antifungals is limited. In this study, we found that calcium supplementation combined with iron deficiency causes dramatic growth inhibition of the human fungal pathogens Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. Calcium induces the downregulation of iron uptake-related genes and, in particular, causes a decrease in the expression of the transcription factor HapX, which tends to transcriptionally activate siderophore-mediated iron acquisition under iron-deficient conditions. Iron deficiency causes calcium overload and the overproduction of intracellular reactive oxygen species (ROS), and perturbed ion homeostasis suppresses fungal growth. These phenomena are consistently identified in azole-resistant A. fumigatus isolates. The findings here imply that low iron availability lets cells mistakenly absorb calcium as a substitute, causing calcium abnormalities. Thus, there is a mutual effect between iron and calcium in fungal pathogens, and the combination of calcium with an iron chelator could serve to improve antifungal therapy. IMPORTANCE Millions of immunocompromised people are at a higher risk of developing different types of severe fungal diseases. The limited number of antifungals and the emergence of antimicrobial resistance highlight an urgent need for new strategies against invasive fungal infections. Here, we report that calcium can interfere with iron absorption of fungal pathogens, especially in iron-limited environments. Thus, a combination of calcium supplementation with an iron chelator inhibits the growth of human fungal pathogens, including Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. Moreover, we demonstrate that iron deficiency induces a nonspecific calcium uptake response, which results in toxic levels of metal. Findings in this study suggest that a microenvironment with excess calcium and limited iron is an efficient strategy to curb the growth of fungal pathogens, especially for drug-resistant isolates.

Use of Retroauricular Flaps to Reconstruct Defects of the Helical Rim and Adjuvant Intralesional Corticosteroids after Resection of Large Keloids.

BACKGROUND: The optimal treatment for large helical rim keloids remains unclear. AIMS: The authors evaluated patient outcomes when retro auricular flaps were used to reconstruct helical rim defects and adjuvant intralesional corticosteroids were prescribed after resection of large keloids. MATERIALS AND METHODS: The authors evaluated 7 females with 12 large keloids of the helical rim (5 patients had lesions in both ears). All patients were aged 18 to 33 years. The authors used retro auricular flaps to reconstruct the helical rim defects and prescribed adjuvant intralesional corticosteroids after resection. The lesion area ranged from 2.5 × 2.0 to 3.5 × 3.5 cm2. The flap size ranged from 2.5 × 3.0 to 3.5 × 4.5 cm2. The flaps and wound bases received 3 steroid injections at approximately 1, 2, and 3 months postoperatively. RESULTS: No flap necrosis or complications were noted. The postoperative esthetic results were satisfactory in 8 patients and excellent in 4. All patients were followed up for 14 to 28 months (median, 20.6 months). No recurrence was noted, although 3 patients exhibited mild scarring of the wound flap base. CONCLUSIONS: A retro auricular flap is safe and effective for reconstructing helical rim defects; adjuvant intralesional corticosteroids prevent scarring of the flap wound base after resection of large keloids.