Perspectives on polarity - exploring biological asymmetry across scales

In this Perspective, Journal of Cell Science invited researchers working on cell and tissue polarity to share their thoughts on unique, emerging or open questions relating to their field. The goal of this article is to feature 'voices' from scientists around the world and at various career stages, to bring attention to innovative and thought-provoking topics of interest to the cell biology community. These voices discuss intriguing questions that consider polarity across scales, evolution, development and disease. What can yeast and protists tell us about the evolution of cell and tissue polarity in animals? How are cell fate and development influenced by emerging dynamics in cell polarity? What can we learn from atypical and extreme polarity systems? How can we arrive at a more unified biophysical understanding of polarity? Taken together, these pieces demonstrate the broad relevance of the fascinating phenomenon of cell polarization to diverse fundamental biological questions.

Targeting XPO1 Combined with Radiotherapy to Enhance Systemic Anti-tumor Effects in Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

The combination of radiation and radiosensitizing chemotherapeutic agents have shown promising anti-tumor effects in NSCLC. Acting as an oncogenic driver, XPO1 is frequently overexpressed and/or mutated in lung cancer. Thus, suppression of XPO1-mediated nuclear export presents a unique therapeutic strategy. We hypothesize that XPO1 inhibition combined with radiotherapy (XRT) may remodel the tumor immune microenvironment (TIME) and reduce radioresistance, thus enhance systemic anti-tumor effects.

MATERIALS/METHODS

Herein, we optimized a small molecule inhibitor, WJ01024, which can bind to XPO1 and antagonize its activity to inhibit nuclear export. In the C57BL/6 mouse subcutaneous tumor model, we evaluated the ability of different treatment regimens containing oral WJ01014 single or combined with XRT (one fractions of 15 Gy) in tumor control and tumor recurrence inhibition. The effects of each treatment regimen on the alterations of immunophenotypes, including the quantification, activation, proliferative capacity, exhaustion marker expression, and memory status, were evaluated by flow cytometry.

RESULTS

In our study, we found that the overexpression of XPO1 was associated with poor prognosis and survival in radioresistant patients with NSCLC. The combination therapy of WJ01024 and XRT resulted in an increase of apoptosis and a decrease of proliferation compared to monotherapy, which was closely correlated with tumor regression and improved survival in the C57BL/6 mouse subcutaneous tumor model. Notably, we found that WJ01024 were shown to enhance the therapeutic effect of XRT by remodeling TIME. Compared with XRT, the addition of WJ01024 increased the infiltration and proliferation of radiation-stimulated CD8+ T cells, which especially promoted the production of interferon-γ and granzyme B. Moreover, the combination therapy also reversed the immunosuppressive effect of radiation on the percentage of Tregs and exhausted T cells in mouse xenografts. Thus, the TIME was significantly improved in combination therapy. Strikingly, mechanistic studies suggested that the activation of cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) signaling pathway is required to reshape TIME and produce synergistic anti-tumor effect with the combination of WJ01024 and XRT.

CONCLUSION

Our findings suggest that WJ01024 might be a potential synergistic treatment for radiotherapy to control the proliferation of NSCLC cells, promote tumor regression and prolong survival in mouse model of NSCLC by activating cGAS/STING signaling, and this in turn potentiate the immune microenvironment.

Single-Cell RNA Sequencing Reveals a Subset of cMAS can Aggravate RIHD through CXCL1-CXCR2 Axis

PURPOSE/OBJECTIVE(S)

Radiation induced heart disease (RIHD) is any form of cardiac toxicity induced by radiation therapy (RT) for thoracic cancers. Our previous studies have shown that RT obviously contributed to cardiovascular diseases-specific death over 3 years while RT became protective in the short term within 2 years survival in non-small cell lung cancer patients. Here, single cell RNA sequencing (scRNA-seq) was performed to identify various cell subsets and investigate their functions and dynamics in RIHD which offered several targets for early clinical interventions to alleviate RIHD.

MATERIALS/METHODS

Based on evaluation of histopathological characteristics, ejection fraction and serum levels of cardiac injury biomarkers, we have established mouse models during different stages to simulate clinical RIHD progression. Hence, we performed single cell RNA-sequencing of RIHD models to characterize the diversity within specific cell types and obtain basic information of differently expressed genes (DEGs). We investigated the role of several cell clusters and DEGs in RIHD through bioinformatics analysis and experimental verification. In vivo, mouse models were given intraperitoneal injection of CXCR2 inhibitor. Bone marrow macrophages and primary cardiac fibroblasts were extracted for in vitro experiments.

RESULTS

RIHD processes were divided into acute injury, compensation and decompensation stage. Transcriptomes of 31769 single cells from cardiac suspension have been profiled. Analysis of scRNA-seq revealed that there were 30 cell clusters participating in RIHD. The fraction of cell populations varied greatly at three stages which indicated RIHD was a dynamic process and each cell cluster functioned differently at different stages. Notably, we observed cardiac resident macrophages (cMAS) subset accounted for the highest fraction during the compensatory period and decreased in decompensation period. Pseudotime analysis showed cMAS had a different developmental trajectory compared to myeloid derived cells. Moreover, CXCR2 was significantly expressed in cMAS cluster. Ligand-receptor interaction results suggested that CXCL1 secreted by cardiac fibroblasts bind primarily to CXCR2+ cMAS and participated in the formation of the extracellular matrix (ECM) related to cardiac fibrosis. Moreover, cardiac fibrosis of RIHD models were relieved after CXCR2 inhibitor treatment. CXCL1 expression in primary cardiac fibroblast elevated after RT.

CONCLUSION

The identification of main cell clusters provided a new insight to investigate RIHD through dynamics of cell phenotypes and cell-cell communications during RIHD processes. In compensation stage, CXCR2+ cMAS could be activated by CXCL1 secreted by cardiac fibroblasts. Both were associated with ECM and contribute to the decompensation stage.

A paternal protein facilitates sperm RNA delivery to regulate zygotic development

Sperm contributes essential paternal factors, including the paternal genome, centrosome, and oocyte-activation signals, to sexual reproduction. However, it remains unresolved how sperm contributes its RNA molecules to regulate early embryonic development. Here, we show that the Caenorhabditis elegans paternal protein SPE-11 assembles into granules during meiotic divisions of spermatogenesis and later matures into a perinuclear structure where sperm RNAs localize. We reconstitute an SPE-11 liquid-phase scaffold in vitro and find that SPE-11 condensates incorporate the nematode RNA, which, in turn, promotes SPE-11 phase separation. Loss of SPE-11 does not affect sperm motility or fertilization but causes pleiotropic development defects in early embryos, and spe-11 mutant males reduce mRNA levels of genes crucial for an oocyte-to-embryo transition or embryonic development. These results reveal that SPE-11 undergoes phase separation and associates with sperm RNAs that are delivered to oocytes during fertilization, providing insights into how a paternal protein regulates early embryonic development.

Feedback regulation of ubiquitination and phase separation of HECT E3 ligases

Lipid homeostasis is essential for normal cellular functions and dysregulation of lipid metabolism is highly correlated with human diseases including neurodegenerative diseases. In the ubiquitin-dependent autophagic degradation pathway, Troyer syndrome-related protein Spartin activates and recruits HECT-type E3 Itch to lipid droplets (LDs) to regulate their turnover. In this study, we find that Spartin promotes the formation of Itch condensates independent of LDs. Spartin activates Itch through its multiple PPAY-motif platform generated by self-oligomerization, which targets the WW12 domains of Itch and releases the autoinhibition of the ligase. Spartin-induced activation and subsequent autoubiquitination of Itch lead to liquid-liquid phase separation (LLPS) of the poly-, but not oligo-, ubiquitinated Itch together with Spartin and E2 both in vitro and in living cells. LLPS-mediated condensation of the reaction components further accelerates the generation of polyubiquitin chains, thus forming a positive feedback loop. Such Itch-Spartin condensates actively promote the autophagy-dependent turnover of LDs. Moreover, we show that the catalytic HECT domain of Itch is sufficient to interact and phase separate with poly-, but not oligo-ubiquitin chains. HECT domains from other HECT E3 ligases also exhibit LLPS-mediated the promotion of ligase activity. Therefore, LLPS and ubiquitination are mutually interdependent and LLPS promotes the ligase activity of the HECT family E3 ligases.

Increased α-HB Links Colorectal Cancer and Diabetes by Potentiating NF-κB Signaling

Sufficient evidence has linked many different types of cancers and T2D through shared risk factors; however, the underlying mechanisms are not fully understood. α-Hydroxybutyrate (α-HB), a byproduct metabolite increased in diabetes and cancer, including colorectal cancer (CRC), triggers lactate dehydrogenase A (LDHA) nuclear translocation. Nuclear LDHA markedly extends NF-κB nuclear retention by interacting with phosphorylated p65, leading to an increase in TNF-α production, impaired insulin secretion and the exacerbation of azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced CRC and high-fat diet (HFD)-induced type 2 diabetes. Furthermore, metformin interrupted this process by inhibiting the transcription of FOXM1 and c-MYC, the resultant downregulation of LDHA expression and α-HB-induced LDHA nuclear translocation. Thus, the results reveal the elevated α-HB level could be a novel shared risk factor of linking CRC, diabetes and the use of metformin treatment, as well as highlight the importance of preventing NF-κB activation for protecting against cancer and diabetes.

Enhanced BCAT1 activity and BCAA metabolism promotes RhoC activity in cancer progression

Increased expression of branched-chain amino acid transaminase 1 or 2 (BCAT1 and BCAT2) has been associated with aggressive phenotypes of different cancers. Here we identify a gain of function of BCAT1 glutamic acid to alanine mutation at codon 61 (BCAT1E61A) enriched around 2.8% in clinical gastric cancer samples. We found that BCAT1E61A confers higher enzymatic activity to boost branched-chain amino acid (BCAA) catabolism, accelerate cell growth and motility and contribute to tumor development. BCAT1 directly interacts with RhoC, leading to elevation of RhoC activity. Notably, the BCAA-derived metabolite, branched-chain α-keto acid directly binds to the small GTPase protein RhoC and promotes its activity. BCAT1 knockout-suppressed cell motility could be rescued by expressing BCAT1E61A or adding branched-chain α-keto acid. We also identified that candesartan acts as an inhibitor of BCAT1E61A, thus repressing RhoC activity and cancer cell motility in vitro and preventing peritoneal metastasis in vivo. Our study reveals a link between BCAA metabolism and cell motility and proliferation through regulating RhoC activation, with potential therapeutic implications for cancers.

Ccdc85c-Par3 condensates couple cell polarity with Notch to control neural progenitor proliferation

Polarity proteins regulate the proliferation and differentiation of neural progenitors to generate neurons during brain development through multiple signaling pathways. However, how cell polarity couples the signaling pathways remains unclear. Here, we show that coiled-coil domain-containing protein 85c (Ccdc85c) interacts with the polarity protein Par3 to regulate the proliferation of radial glial cells (RGCs) via phase separation coupled to percolation (PSCP). We find that the interaction with Ccdc85c relieves the intramolecular auto-inhibition of Par3, which leads to PSCP of Par3. Downregulation of Ccdc85c causes RGC differentiation. Importantly, the open conformation of Par3 facilitates the recruitment of the Notch regulator Numb to the Par3 condensates, which might prevent the attenuation of Notch activity to maintain RGC proliferation. Furthermore, ectopic activation of Notch signaling rescues RGC proliferation defects caused by the downregulation of Ccdc85c. These results suggest that Ccdc85c-mediated PSCP of Par3 regulates Notch signaling to control RGC proliferation during brain development.

Protein phase separation: new insights into cell division

As the foundation for the development of multicellular organisms and the self-renewal of single cells, cell division is a highly organized event which segregates cellular components into two daughter cells equally or unequally, thus producing daughters with identical or distinct fates. Liquid-liquid phase separation (LLPS), an emerging biophysical concept, provides a new perspective for us to understand the mechanisms of a wide range of cellular events, including the organization of membrane-less organelles. Recent studies have shown that several key organelles in the cell division process are assembled into membrane-free structures via LLPS of specific proteins. Here, we summarize the regulatory functions of protein phase separation in centrosome maturation, spindle assembly and polarity establishment during cell division.

Cell Cycle-Related FAM64A Could be Activated by TGF-β Signaling to Promote Glioma Progression

Gliomas are aggressive brain tumors characterized by uncontrolled cell proliferation. FAM64A, a cell cycle-related gene, has been found to promote cell proliferation in various tumors, including gliomas. However, the regulatory mechanism and clinical significance of FAM64A in gliomas remain unclear. In this study, we investigated FAM64A expression in gliomas with different grades and constructed FAM64A silenced cell lines to study its functions. Our results demonstrated that FAM64A was highly expressed in glioblastoma (P < 0.001) and associated with a poor prognosis (P < 0.001). Expression profiles at the single-cell resolution indicated FAM64A could play a role in a cell-cycle-dependent way to promote glioma cell proliferation. We further observed that FAM64A silencing in glioma cells resulted in disrupted proliferation and migration ability, and increased cell accumulation in the G2/M phase (P = 0.034). Additionally, TGF-β signaling upregulates FAM64A expression, and SMAD4 and FAM64A co-localize in high-grade glioma tissues. We found FAM64A knockdown inhibited TGF-β-induced epithelial-mesenchymal transition in glioma. Our findings suggest that FAM64A could serve as a diagnostic and therapeutic target in gliomas.

Palmitoylation of MDH2 by ZDHHC18 activates mitochondrial respiration and accelerates ovarian cancer growth

Epithelial ovarian cancer (EOC) exhibits strong dependency on the tricarboxylic acid (TCA) cycle and oxidative phosphorylation to fuel anabolic process. Here, we show that malate dehydrogenase 2 (MDH2), a key enzyme of the TCA cycle, is palmitoylated at cysteine 138 (C138) residue, resulting in increased activity of MDH2. We next identify that ZDHHC18 acts as a palmitoyltransferase of MDH2. Glutamine deprivation enhances MDH2 palmitoylation by increasing the binding between ZDHHC18 and MDH2. MDH2 silencing represses mitochondrial respiration as well as ovarian cancer cell proliferation both in vitro and in vivo. Intriguingly, re-expression of wild-type MDH2, but not its palmitoylation-deficient C138S mutant, sustains mitochondrial respiration and restores the growth as well as clonogenic capability of ovarian cancer cells. Notably, MDH2 palmitoylation level is elevated in clinical cancer samples from patients with high-grade serous ovarian cancer. These observations suggest that MDH2 palmitoylation catalyzed by ZDHHC18 sustains mitochondrial respiration and promotes the malignancy of ovarian cancer, yielding possibilities of targeting ZDHHC18-mediated MDH2 palmitoylation in the treatment of EOC.

Hippocampal cingulum white matter increases over time in young people at high genetic risk for bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a strongly familial psychiatric disorder associated with white matter (WM) brain abnormalities. It is unclear whether such abnormalities are present in relatives without BD, and little is known about WM trajectories in those at increased genetic risk.

METHODS

Diffusion magnetic resonance imaging (dMRI) data were acquired at baseline and after two years in 91 unaffected individuals with a first-degree relative with bipolar disorder (HR), and 85 individuals with no family history of mental illness (CON). All participants were aged between 12 and 30 years at baseline. We examined longitudinal change in Fractional Anisotropy (FA) using tract-based spatial statistics (TBSS).

RESULTS

Compared to the CON group, HR participants showed a significant increase in FA in the right cingulum (hippocampus) (CGH) over a two-year period (p < .05, FDR corrected). This effect was more pronounced in HR individuals without a lifetime diagnosis of a mood disorder than those with a mood disorder.

LIMITATIONS

While our study is well powered to achieve the primary objectives, our sub-group analyses were under powered.

CONCLUSIONS

In one of the very few longitudinal neuroimaging studies of young people at high risk for BD, this study reports novel evidence of atypical white matter development in HR individuals in a key cortico-limbic tract involved in emotion regulation. Our findings also suggest that this different white matter developmental trajectory may be stronger in HR individuals without affective psychopathology. As such, increases in FA in the right CGH of HR participants may be a biomarker of resilience to mood disorders.

Efficacy and safety of outpatient parenteral antibiotic therapy in patients with infective endocarditis: a meta-analysis

OBJECTIVE

To investigate the clinical outcome of patients with infective endocarditis (IE) during and after outpatient parenteral antimicrobial treatment (OPAT), and to further clarify the safety and efficacy of OPAT for IE patients.

METHODS

Through December 20, 2021, a total of 331 articles were preliminarily searched in Pubmed, Web of Science, Cochrane Library and Embase, and 9 articles were eventually included in this study.

RESULTS

A total of 9 articles comprising 1,116 patients were included in this study. The overall mortality rate of patients treated with OPAT was 0.04 (95% CI, 0.02-0.07), that means 4 deaths per 100 patients treated with OPAT. Separately, mortality was low during the follow-up period after OPAT treatment, with an effect size (ES) of 0.03 (95%CI, 0.02-0.07) and the mortality of patients during OPAT treatment was 0.04 (95% CI, 0.01-0.12). In addition, the readmission rate was found to be 0.14 (95% CI, 0.09-0.22) during the follow-up and 0.18 (95% CI, 0.08-0.39) during treatment, and 0.16 (95% CI, 0.10-0.24) for patients treated with OPAT in general. Regarding the relapse of IE in patients, our results showed a low overall relapse rate, with an ES of 0.03 (95% CI, 0.01-0.05). In addition, we found that the incidence of adverse events was low, with an ES of 0.26 (95% CI, 0.19-0.33).

CONCLUSIONS

In general, the incidence of adverse events and mortality, readmission, and relapse rates in IE patients treated with OPAT are low both during treatment and follow-up period after discharge, indicating that OPAT is safe and effective for IE patients. However, our study did not compare routine hospitalization as a control group, so conclusions should be drawn with caution. In order to obtain more scientific and rigorous conclusions and reduce clinical risks, it is still necessary to conduct more research in this field and improve the patient selection criteria for OPAT treatment, especially for IE patients. Finally, clinical monitoring and follow-up of OPAT-treated patients should be strengthened.

[Advances in MRI research on extraocular muscles and pulleys]

With the continuous development of imaging technology, high-resolution magnetic resonance imaging (MRI) can be used to quantitatively analyze the morphological and functional status of orbital soft tissue. Changes in the morphology and function of the extraocular muscles and pulleys may be the mechanical basis of some incomitant and special patterns of strabismus. Recent MRI research advances related to the characteristics of extraocular muscles and pulleys of healthy people and strabismic patients are reviewed in this article.

Effectiveness of Family-Centered Oral Health Promotion on Toddler Oral Health in Hong Kong

Early childhood caries is common in Hong Kong, and parental practices on maintaining good oral health of their young children are far from satisfactory. This article reports on the effectiveness of a randomized controlled trial on family-centered oral health promotion to new parents in establishing proper feeding habits and oral hygiene practices and in reducing caries risk among 3-y-old toddlers. At baseline, pregnant mothers and their husbands were recruited and randomly allocated into 2 groups. The test group received individualized oral health education (OHE) via a behavioral and educational counseling approach while the control group received the OHE pamphlets only. Information related to the feeding habits, oral hygiene practices, and oral health of the toddlers was collected by parent-completed questionnaires and oral examination annually via home visits. A total of 580 families were recruited at baseline, and 436 toddlers were followed up when they reached 3 y old (test, n = 228; control, n = 208; follow-up rate, 75.2%). The proportions of toddlers who held food in the mouth, fell asleep when milk feeding, had prolonged use of the nursing bottle, ate before bed, and consumed a sweet snack daily were significantly lower in the test group than in the control group (all P < 0.05). Significantly higher proportions of toddlers brushed their own teeth twice daily, were brushed by their parents twice daily, and used fluoride toothpaste than in the control group (all P < 0.001). Toddlers in the test group had better oral health status with a lower level of visible plaque, Streptococcus mutans, white spot lesion, and cavitated lesion (all P < 0.05). Family-centered oral health promotion and individualized OHE for parents via a behavioral and educational counseling approach are more effective in establishing good feeding habits and parental toothbrushing practices and in decreasing the caries risk of their toddlers than the distribution of OHE pamphlets alone (ClinicalTrials.gov NCT02937194).

Phase Separation in Cell Polarity

Cells are biochemically and morphologically polarized, which allows them to produce different cell shapes for various functions. Remarkably, some polarity protein complexes are asymmetrically recruited and concentrated on limited membrane regions, which is essential for the establishment and maintenance of diverse cell polarity. Though the components and mutual interactions within these protein complexes have been extensively investigated, how these proteins autonomously concentrate at local membranes and whether they have the same organization mechanism in the condensed assembly as that in aqueous solution remain elusive. A number of recent studies suggest that these highly concentrated polarity protein assemblies are membraneless biomolecular condensates which form through liquid-liquid phase separation (LLPS) of specific proteins. In this perspective, we summarize the LLPS-driven condensed protein assemblies found in asymmetric cell division, epithelial cell polarity, and neuronal synapse formation and function. These findings suggest that LLPS may be a general strategy for cells to achieve local condensation of specific proteins, thus establishing cell polarity.

O-174 Individualized versus standard FSH dosing in predicted poor responders: an RCT

Study question

Is there a difference in fertility outcomes between individualized or standard FSH dosing in women scheduled for IVF with an expected poor response?

Summary answer

In predicted poor responders (AFC&lt;10) undergoing IVF/ICSI, individualized FSH dosing does not improve ongoing pregnancy rates as compared to a standard FSH dose.

What is known already

Poor responders usually lead to many detrimental effects on IVF outcomes due to low oocyte number and quality which in turn result in low pregnancy outcomes and an increased chance of cycle cancellation. Clinicians often individualize the FSH dose using ovarian reserve tests (ORT), including antral follicle count (AFC), basal FSH (bFSH), and anti-Mullerian hormone (AMH). However, it is unclear whether individualized FSH dosing improves clinical outcomes.

Study design, size, duration

Between March 2019 and April 2020, we performed a single-center, parallel, open-label RCT in women with an AFC&lt;10. A total of 661 women were randomized either to start FSH dosing at 300IU/225IU or 150IU. The primary outcome was live birth attributable to the first ART cycle within 18 months of randomization. In this abstract, we report ongoing pregnancy rates. Live birth date will be available at the meeting.

Participants/materials, setting, methods

Women referred for their first IVF/ICSI cycle, &lt;43 years of age, AFC&lt;10 were approached. A total of 328 women were allocated to the individualized group and 333 women were allocated to the standard group. In the individualized group, women with AFC 1-6 were assigned to 300IU/day (n = 122), while women with AFC 7-9 were assigned to 225IU/day (n = 206). In the standard group, women were assigned 150IU/day. Outcomes were evaluated from an intention-to-treat perspective.

Main results and the role of chance

For ongoing pregnancy rate attributable to the first ART cycle for individualized versus standard dosing was comparable [52.44% vs 46.25%, relative risk (RR): 1.29 (95%CI, 0.94-1.74), P = 0.11]. Biochemical pregnancy rate [62.50% vs 62.16%, RR: 1.01 (95%CI, 0.74-1.39), P = 0.929], clinical pregnancy rate [59.45% vs 58.86%, RR: 1.02 (95%CI, 0.75-1.40), P = 0.877] and multiple pregnancy rate [5.18% vs 5.12%, RR: 1.01 (95%CI, 0.51-2.02), P = 0.971] also did not differ between individualized and standard dosing. There are 24 women who are ongoing pregnancy but do not reach live birth in the completed embryo transfer cycle. The individualized group reported less poor response (31.1% vs 48.7%: P &lt; 0.001), more obtained oocytes (6.80 ± 3.85 vs 5.28 ± 3.22; P &lt; 0.001), less embryos (3.76 ± 2.70 vs 3.16 ± 2.42; P = 0.004), and less good quality embryos (2.61 ± 2.29 vs 2.21 ± 2.05; P = 0.018). When outcomes were compared over the first embryo transfer, ongoing pregnancy rates were 39.0% (128/328) versus 37.2% (124/333), respectively [RR:1.08 (95%CI, 0.79-1.48), P = 0.636], without differences in the other outcomes. There are 7 women who are ongoing pregnancy but do not reach live birth in the first embryo transfer cycle.

Limitations, reasons for caution

Due to the open-label character, potential selective canceling and small dose adjustments of standard dosing were allowed. This abstract reports on ongoing pregnancy. At the meeting, we will present live birth rates.

Wider implications of the findings

In women with predicted poor response, an increased dose does not increase ongoing pregnancy rates. A standard dose of 150IU/day is recommended in these women.

Trial registration number

ChiCTR1900021944

Impacts of COVID-19 on the electric vehicle industry: Evidence from China

Electric vehicle development is critical to achieve the sustainable goals, while the hit of COVID-19 strikes the market and brings challenges to the whole industry. China, among one of the earliest regions affected by COVID-19 and takes a great part in the global electric vehicle market, is attracting growing attention on its post-pandemic trends in the electric vehicle industry. This paper provides a comprehensive analysis of COVID-19 impacts on China's electric vehicle industry from both the demand side and the supply side. Both challenges and opportunities for China's electric vehicle development are revealed with emerging trend analysis. It is found that the COVID-19 outbreak has reduced electric vehicle sales in the short-term, but may also stimulate future electric vehicle demand especially for large electric cars with better performance. Meanwhile, travel restrictions caused by COVID-19 have interrupted electric vehicle material supplies that relying on imports, accelerating domestic substitute exploitation and inventory improvement for critical parts. Additionally, massive lockdowns for controlling COVID-19 have disrupted productions and operations, which tends to expel small brands out of the competitive market, concentrating China's electric vehicle industry to the leading brands. Finally, the social distancing trend after pandemic is bringing challenges to traditional EV distribution channels with dealers, pushing automakers to develop innovative online selling channels. These impacts are likely to lead to a reformation of China's electric vehicle industry towards a more advanced and reliable future.

[Diagnosis and treatment of Chlamydia psittaci pneumonia: experiences of 8 cases]

Objective: In order to improve the understanding and clinical treatment of Chlamydia psittaci pneumonia, we analyzed the clinical manifestations, laboratory test results and imaging features of 8 patients. Methods: We collected the clinical data of 8 patients with Chlamydia psittaci pneumonia diagnosed by metagenomic next-generation-sequencing (mNGS) from November 2018 to February 2020, including clinical features, chest CT scan, pathological features and antibiotic use. Results: A total of one male and 7 females, aged from 45 to 85 years(median 62 years), were included in this study. All the patients had high fever, cough and most had expectoration (6/8). The leukocyte count and PCT level were mostly normal (7/8). However, we observed decreased lymphocyte count(5/8), elevated C-reactive protein in all patients, and increased ESR in most patients (7/8). The chest CT of all the patients showed large patchy consolidation, with one case having pleural effusion. The pathological manifestations were nonspecific, showing infiltration of inflammatory cells and exudation. Moxifloxacin and/or doxycycline were administered after diagnosis, and the course of treatment lasted from 14 to 21 days.Chest CT showed absorption of lesions following treatment Conclusions: Chlamydia psittaci pneumonia showed certain characteristics, including high fever with pulmonary patchy consolidation, and normal white blood cell count. Molecular diagnostic methods such as mNGS could lead to rapid diagnosis and treatment which can shorten the course of hospitalization and thus improve prognosis.

FOXM1D potentiates PKM2-mediated tumor glycolysis and angiogenesis

Tumor growth, especially in the late stage, requires adequate nutrients and rich vasculature, in which PKM2 plays a convergent role. It has been reported that PKM2, together with FOXM1D, is upregulated in late-stage colorectal cancer and associated with metastasis; however, their underlying mechanism for promoting tumor progression remains elusive. Herein, we revealed that FOXM1D potentiates PKM2-mediated glycolysis and angiogenesis through multiple protein-protein interactions. In the presence of FBP, FOXM1D binds to tetrameric PKM2 and assembles a heterooctamer, restraining PKM2 metabolic activity by about a half and thereby promoting aerobic glycolysis. Furthermore, FOXM1D interacts with PKM2 and NF-κB and induces their nuclear translocation with the assistance of the nuclear transporter importin 4. Once in the nucleus, PKM2 and NF-κB complexes subsequently augment VEGFA transcription. The increased VEGFA is secreted extracellularly via exosomes, an event potentiated by the interaction of FOXM1 with VPS11, eventually promoting tumor angiogenesis. Based on these findings, our study provides another insight into the role of PKM2 in the regulation of glycolysis and angiogenesis.

[The correlations between C-reactive protein to albumin ratio and postoperative complications in patients with colorectal surgery]

Objective: To examine the correlations of C-reactive protein (CRP)/albumin ratio (CAR) with the postoperative complications of patients with colorectal cancer. Methods: The clinic data of 312 patients undergoing elective surgery for colorectal cancer in Hainan Hospital of People's Liberation Army General Hospital between January 2013 and July 2018 was analyzed retrospectively. There were 188 males and 124 females, aged (61.0±12.9) years (range: 21 to 86 years). Logistic analysis was used to identify relative factors for postoperative complications. Receiver operating characteristic curves were developed to examine the cutoff values and compare diagnostic accuracy of the CAR and CRP levels. Results: Postoperative complications occured in 28.5% (89/312) cases. Hemoglobin on postoperative day(POD) 3 (OR=0.977, 95% CI: 0.957 to 0.998, P=0.034), preoperative CRP (OR=1.209, 95% CI: 1.055 to 1.386, P=0.006) and CAR on POD 3 (OR=0.033, 95% CI: 0.016 to 0.067, P<0.01) were found to be significant independent relative factors for postoperative complications. The cutoff point of CAR on POD 3 was 0.325, patients with CAR≥0.325 were found to have more postoperative complications than those with CAR<0.325. The area under the curve of CAR on POD 3 and preoperative CRP were 0.872, 0.626, respectively. The positive predictive value of CAR on POD 3 was higher than that of preoperative CRP (79.9% vs. 55.1%). Conclusions: CAR is closely related to the occurrence of postoperative complications in colorectal surgery. Patients with CAR≥0.325 on POD 3 has higher incidence of postoperative complications.

Do distribution and expansion of exotic invasive Asteraceae plants relate to leaf construction cost in a man-made wetland?

Exotic species especially Asteraceae plants severely invade wetlands in Shenzhen Bay, an important part of the coast wetland in Guangdong-Hong Kong-Macau Bay Area, China. However, the reasons causing their expansion are unclear. The leaf traits and expansion indices of six invasive Asteraceae plants from the Overseas Chinese Town (OCT) wetland were studied and the results showed that nearly 45% of the total plant species (31 out of 69 species) in the OCT wetland, belonging to 15 families and 27 genera, were exotic invasive species. The expansion indices of six Asteraceae species negatively correlated with their leaf construction cost based on mass (CCM), caloric values and carbon concentration, but their relations with ash content were positive. Multiple linear regression analysis revealed that CCM was the most important factor affecting the expansion of an exotic species, indicating CCM may be an important reason causing the expansion of exotic species in coastal wetlands.

The diagnostic value of lower glucose consumption for IDH1 mutated gliomas on FDG-PET

Background

Non-invasive diagnosis of IDH1 mutation for gliomas has great clinical significance, and PET has natural advantage to detect metabolism, as IDH mutated gliomas share lower glucose consumption.

Methods

Clinical data of patients with gliomas and ¹⁸F-FDG PET were retrospectively reviewed. Receiver operating characteristic curve (ROC) analysis was conducted, and standard uptake value (SUV) was estimated in combination with grades or IDH1 mutation. The glucose consumption was investigated with U251 cells expressing wild-type or mutated IDH1 by glucose assay. Quantification of glucose was determined by HPLC in clinical tissues. Meanwhile, bioinformatics and western blot were applied to analyze the expression level of metabolic enzymes (e.g. HK1, PKM2, PC) in gliomas.

Results

Seventy-one glioma cases were enrolled, including 30 carrying IDH1 mutation. The sensitivity and specificity dependent on SUV_max (3.85) predicting IDH1 mutation reached 73.2 and 86.7%, respectively. The sensitivity and specificity of differentiating grades by SUVmax (3.1) were 92.3 and 64.4%, respectively. Glucose consumption of U251 IDH1 mutant cells (0.209 ± 0.0472 mg/ml) was obviously lower than IDH1wild-type cells (0.978 ± 0.0773 mg/ml, P = 0.0001) and astrocyte controls (0.335 ± 0.0592 mg/ml, P = 0.0451). Meanwhile, the glucose quantity in IDH1mutant glioma samples were significantly lower than those in IDH1 wild-type tissues (1.033 ± 1.19608 vs 6.361 ± 4.3909 mg/g, P = 0.0051). Silico analysis and western blot confirmed that HK1 and PKM2 in IDH1 wild-type gliomas were significantly higher than in IDH1 mutant group, while PC was significantly higher in IDH1 mutant gliomas.

Conclusion

SUV_max on PET can predict IDH1 mutation with adequate sensitivity and specificity, as is supported by reduced glucose consumption in IDH1 mutant gliomas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07797-6.

Arrhythmia in patients with severe coronavirus disease (COVID-19): a meta-analysis

OBJECTIVE

Many studies have reported arrhythmia to be associated with coronavirus disease (COVID-19), but no meta-analysis has explored whether arrhythmia is related to COVID-19 severity. Therefore, the purpose of this study was to evaluate arrhythmia in patients with severe and non-severe COVID-19 during the current COVID-19 pandemic.

MATERIALS AND METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library for case control studies that were published between January 1 and July 25, 2020, and that had data on arrhythmia in patients with COVID-19. Random effects model was used with the odds ratio as the effect size. The frequency of arrhythmia was compared between COVID-19 patients with and without the composite endpoint of severity. We also determined the pooled prevalence of arrhythmia in patients with COVID-19. Publication bias and heterogeneity were considered by using subgroup analyses, meta-regression, and the trim and fill method.

RESULTS

A total of 1553 patients with COVID-19 were included in the 5 articles we obtained. Of these, 349 cases (22.47%) and 1204 cases (77.53%) were severely ill and non-severely ill inpatients with COVID-19 pneumonia, respectively. There were 790 (50.87%) male patients. A total of 105 cases (30.09%) of severely ill inpatients with COVID-19 pneumonia had arrhythmia complications, and 34 cases (2.82%) of non-severely ill inpatients with COVID-19 pneumonia had arrhythmia complications. We found arrhythmia to be significantly associated with severely ill inpatients with COVID-19 pneumonia, with a pooled odds ratio of 17.97 (95% CI (11.30, 28.55), p<0.00001).

CONCLUSIONS

This study showed that the incidence of arrhythmia in patients with severe COVID-19 was greater than that of those with non-severe COVID-19. Patients with severe COVID-19 had a higher risk of arrhythmia complications, which further showed that COVID-19 may be a risk factor for arrhythmia and that the incidence of arrhythmia may increase with the progression of the disease. More importantly, this meta-analysis graded the reliability of evidence for further basic and clinical research into arrhythmia in patients with COVID-19.

Effect of conservative treatment in aortoiliac occlusive disease

Objective: To determine the effect of primary conservative treatment without revascularization in patients with proven aortoiliac occlusive disease (AIOD) presenting with intermittent claudication (IC).Background: The initial treatment of IC should focus on supervised exercise therapy (SET) and pharmacotherapy. Nowadays, primary endovascular revascularization (EVR) has become increasingly popular in patients with all types of AIOD. But in daily practice, EVR is often performed without initially extensive exercise.Method: This is a single centre retrospective study from December 2012 to September 2017. Primary outcomes were maximum walking distance (MWD) and patient satisfaction. Secondary outcomes were revascularization rate and mortality.Results: Twenty-four patients were included. Mean age was 64 years (SD: 9). Mean follow-up was 28 months (SD: 17). Nineteen patients (80%) had SET. In 18 (75%) patients, the MWD was improved compared to the initial situation. In five (21%) patients, the MWD stayed the same. The MWD of one (4%) patient decreased. Overall satisfaction rate was 87%. Three patients (13%) were not satisfied with the conservative treatment and eventually got an EVR. There was no disease related death.Conclusions: Conservative treatment, especially with SET, has acceptable subjective symptom outcomes in selected patients with AIOD. It could be a good alternative treatment for certain patients with AIOD and IC.

Par complex cluster formation mediated by phase separation

The evolutionarily conserved Par3/Par6/aPKC complex regulates the polarity establishment of diverse cell types and distinct polarity-driven functions. However, how the Par complex is concentrated beneath the membrane to initiate cell polarization remains unclear. Here we show that the Par complex exhibits cell cycle-dependent condensation in Drosophila neuroblasts, driven by liquid–liquid phase separation. The open conformation of Par3 undergoes autonomous phase separation likely due to its NTD-mediated oligomerization. Par6, via C-terminal tail binding to Par3 PDZ3, can be enriched to Par3 condensates and in return dramatically promote Par3 phase separation. aPKC can also be concentrated to the Par3N/Par6 condensates as a client. Interestingly, activated aPKC can disperse the Par3/Par6 condensates via phosphorylation of Par3. Perturbations of Par3/Par6 phase separation impair the establishment of apical–basal polarity during neuroblast asymmetric divisions and lead to defective lineage development. We propose that phase separation may be a common mechanism for localized cortical condensation of cell polarity complexes.

The evolutionarily conserved complex, the Par proteins, regulates cell polarity. Here, the authors show that in Drosophila neuroblasts, the Par complex exhibits liquid–liquid phase separation dependent on the cell cycle.

Arginine methylation of ribose-5-phosphate isomerase A senses glucose to promote human colorectal cancer cell survival

Cancer cells remodel their metabolic network to adapt to variable nutrient availability. Pentose phosphate pathway (PPP) plays protective and biosynthetic roles by oxidizing glucose to generate reducing power and ribose. How cancer cells modulate PPP activity in response to glucose supply remains unclear. Here we show that ribose-5-phosphate isomerase A (RPIA), an enzyme in PPP, directly interacts with co-activator associated arginine methyltransferase 1 (CARM1) and is methylated at arginine 42 (R42). R42 methylation up-regulates the catalytic activity of RPIA. Furthermore, glucose deprivation strengthens the binding of CARM1 with RPIA to induce R42 hypermethylation. Insufficient glucose supply links to RPIA hypermethylation at R42, which increases oxidative PPP flux. RPIA methylation supports ROS clearance by enhancing NADPH production and fuels nucleic acid synthesis by increasing ribose supply. Importantly, RPIA methylation at R42 significantly potentiates colorectal cancer cell survival under glucose starvation. Collectively, RPIA methylation connects glucose availability to nucleotide synthesis and redox homeostasis.

Phase Separation in Asymmetric Cell Division

Asymmetric cell division (ACD) is a conserved strategy for achieving cell diversity. A cell can undergo an intrinsic ACD through asymmetric segregation of cell fate determinants or cellular organelles. Recently, a new biophysical concept known as biomolecular phase separation, through which proteins and/or RNAs autonomously form a highly concentrated non-membrane-enclosed compartment via multivalent interactions, has provided new insights into the assembly and regulation of many membrane-less or membrane-attached organelles. Intriguingly, biomolecular phase separation is suggested to drive asymmetric condensation of cell fate determinants during ACD as well as organization of cellular organelles involved in ACD. In this Perspective, I first summarize recent findings on the molecular basis governing intrinsic ACD. Then I will discuss how ACD might be regulated by formation of dense molecular assemblies via phase separation.

A multi-lock inhibitory mechanism for fine-tuning enzyme activities of the HECT family E3 ligases

HECT E3 ligases control the degradation and functioning of numerous oncogenic/tumor-suppressive factors and signaling proteins, and their activities must be tightly regulated to prevent cancers and other diseases. Here we show that the Nedd4 family HECT E3 WWP1 adopts an autoinhibited state, in which its multiple WW domains sequester HECT using a multi-lock mechanism. Removing WW2 or WW34 led to a partial activation of WWP1. The structure of fully inhibited WWP1 reveals that many WWP1 mutations identified in cancer patients result in a partially active state with increased E3 ligase activity, and the WWP1 mutants likely promote cell migration by enhancement of ∆Np63α degradation. We further demonstrate that WWP2 and Itch utilize a highly similar multi-lock autoinhibition mechanism as that utilized by WWP1, whereas Nedd4/4 L and Smurf2 utilize a slightly variant version. Overall, these results reveal versatile autoinhibitory mechanisms that fine-tune the ligase activities of the HECT family enzymes.

HECT type E3 ligases are key regulators of cell growth and proliferation. Here the authors present the crystal structures of the Nedd4 family E3 ligase WWP1 in a closed and semi-open state and in combination with mutagenesis experiments identify a multi-lock regulatory mechanism that allows the fine-tuning of activities of Nedd4 family E3 ligases.

[The effect of trabeculectomy combined with prophylactic sclerotomy as a treatment of late stage juvenile open angle glaucoma and primary congenital glaucoma patients: a primary observational study]

Objective: To evaluate the outcomes of trabeculectomy combined with a new prophylactic sclerotomy in late stage juvenile open angle glaucoma (JOAG) and primary congenital glaucoma (PCG) patients at high risks of intraoperative and postoperative suprachoroidal hemorrhage (SCH). Method: A retrospective case series study. Thirty-three eyes of 28 JOAG patients and 15 eyes of 12 PCG patients with high risk factors for severe choroidal effusion or SCH were enrolled from November 2006 to April 2012 at Eye and ENT Hospital of Fudan University. The standard trabeculectomy accompanied by prophylactic sclerotomy was performed (video attached). Ophthalmic examinations were performed before and after the surgery. Surgical outcome was assessed in terms of intraocular pressure (IOP), best-corrected visual acuity, optic nerve head cup disc ratio, visual field, and complications. All patients were followed up for at least 1 year. Complete success was defined as an IOP ≥6 mmHg (1 mmHg=0.133 kPa) but ≤18 mmHg without medication. Qualified success was defined as an IOP ≥6 mmHg but ≤18 mmHg with local application of medications. Kaplan-Meier survival curves were drawn for the success rate calculation. Results: The mean age of all 40 patients was (13.2±9.4) years old. And among them, 22 patients were male and 18 patients were female. The mean follow-up time was (31.8±15.9) months. At the postoperative 3(rd) year, the complete success rate was 75.8%, and the qualified success rate was 90.0%. In our case series, one eye had expulsive SCH intraoperatively and two eyes had delayed SCH postoperatively. All of them were successfully saved without further surgery and with no significant damage to visual function. Conclusion: Trabeculectomy combined with prophylactic sclerotomy is a promising technique developed to control IOP in late stage JOAG and PCG patients, which provides a potential intervention to reduce severe consequences of massive choroidal effusion or SCH. (Chin J Ophthalmol, 2019, 55: 347-354).

[Association between resting heart rate trajectory pattern and risk of cardiovascular and cerebrovascular diseases]

Objective: To examine whether the long-term resting heart rate (RHR) pattern can predict the risk of cardiovascular and cerebrovascular diseases (CVDs). Methods: This prospective cohort study included 63 040 participants who took part in the health examination in 2006 and one of the health examinations on 2008 or 2010 and were free of myocardial infarction, stroke, arrhythmia, cancer and not treated with β-recepter blocker. The outcomes were the first occurrence of myocardial infarction and stroke during the follow up ended on December 31, 2015. RHRs were measured in 2006, 2008, and 2010. We used latent mixture modeling SAS Proc procedure to identify RHR trajectories. We identified 4 distinct RHR trajectory patterns based on the data derived from 2006 and on the pattern change during 2006 to 2010 (low-stable, moderate-stable, moderate-increasing, elevated-decreasing). Collected the general clinical data of the patients. Cox regression model was used to determine the association between RHR trajectory patterns and the risk of CVDs during follow up. Hazard ratio (HR) with 95% confidence intervals (CI) were calculated using Cox regression modeling. Results: There were statistical significance among the 4 distinct RHR trajectory patterns on the following variables: age, gender, smoking status, drinking status, physical activity, education status, history of use antihypertensive drugs, history of hypertension,history of diabetes, body mass index, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting blood glucose, and the level of high-sensitivity C-reactive protein (all P<0.01). The moderate-increasing pattern experienced the highest risk of developing stroke and CVDs among all 4 patterns. The cumulative incidence of cerebral infarction, cerebral hemorrhage and CVDs in the order of low-stable trajectory, moderate-stable trajectory and moderate-increasing trajectory. The cumulative incidences of cerebral infarction, cerebral hemorrhage and CVDs in elevated-decreasing trajectory group were significantly lower than those in moderate-increasing trajectory group, but higher than those in moderate-stable trajectory group. Compared to the low-stable pattern, adjusted HR was 1.3 (95%CI 1.0-1.6) for the moderate-increasing pattern after adjustment for potential confounders. Conclusion: Our study finds that individuals with moderate-increasing RHR trajectory pattern are associated with higher risk of cardiovascular and CVDs.

Infection with sodA mutant of S. Typhimurium leads to up-regulation of autophagy in Raw264·7 macrophages

Salmonella enterica serovar Typhimurium (S. Typhimurium) inhabits a wide range of hosts, including poultry, and causes acute gastroenteritis in humans that may result in death. Superoxide dismutase (SOD) is an important antioxidant enzyme present in nearly all living cells exposed to oxygen. Recently, we reported the novel roles of SOD in serum resistance and biofilm formation in S. Typhimurium. This study was designed to explore the effect of infection with sodA mutant of S. Typhimurium on the autophagic response of macrophages. Murine macrophage cell line RAW264·7 was infected with wild-type (LSM52), a sodA deletion mutant (LSM52ΔsodA) and complemented strain (LSM52CΔsodA). We found that sodA deletion triggered remarkable autophagic responses in infected cells, shown as higher concentrations of LC3-II or Beclin-1 than those infected with the wild-type or complemented strain during the first hour post-infection in S. Typhimurium. Consistent with these results, the number of viable bacteria in cells infected with the sodA mutant was significantly lower than those infected with wild-type or complemented strains at 1 h, 2 h and 3 h post-infection in S. Typhimurium. All results indicated that infection with sodA mutant of S. Typhimurium leads to up-regulation of autophagy in Raw264·7 macrophages. SIGNIFICANCE AND IMPACT OF THE STUDY: Autophagy plays an important role in Salmonella infection although the role of autophagy in Salmonella infection remains unclear. This study was designed to explore the effect of sodA on the autophagic response of macrophage. We found that infection with sodA mutant of Salmonella Typhimurium could lead to up-regulation of autophagy in Raw264·7 macrophages.

[Epidemiological investigation and analysis of an outbreak of mycoplasma pneumoniae pneumonia in adult]

Objective: To conduct an epidemiological investigation and analysis of an outbreak of mycoplasma pneumonia in adults. Methods: The first case was a 23-year-old male came from the Third Military Medical University, who served as an intern in the Fuzhou General Hospital of PLA and presented on July 16, 2015 with a history of low-grade fever, dizziness, fatigue and chest tightness. Chest CT revealed pulmonary nodules shadow. It was found that other 11 individuals who had been in close contact with the first patient also had similar pulmonary nodules shadow after chest CT examination. Immediately, the health and epidemic prevention department of the ministry of health of Nanjing Military Command and the disease prevention and control center of the Nanjing Military Command received a phone call from Fuzhou General Hospital of PLA. Upon arrival, the prevention and control team conducted a series of epidemiological investigations and on-site prevention, control and disposal of the event, and conducted chest CT screening for other 289 students and staff who volunteered to be examined living in the same area. After the patients with similar pulmonary nodules shadow were screened out, mycoplasma antibody titer detection and chest CT re-scanning were performed for compliance patients. Results: There were 301 students living in the dormitories (Building A and B) of the student living area, and they were screened by chest CT, and it was found that 27 of them had pulmonary nodules shadow, including single pulmonary nodules shadow (48.1%, 13 out of 27) and multiple pulmonary nodules shadow (51.9%, 14 out of 27). And halo sign was observed in 25 of 27 patients (92.6%). The majority of the 27 patients were asymptomatic, only 2 patients got cough, a few of them had systemic symptoms such as fever, dizziness, fatigue. The positive rate of pulmonary nodules shadow was 32.8% (22/67) in building A (poor environmental hygiene), 2.14% (5/234) in building B, and the total incidence rate was 8.97%. Four-fold increase in the mycoplasma pneumoniae (MP) antibody titer in the paired sera was observed in first 12 patients. Measures such as disinfection, isolation and sanitation were taken to control the spread of the epidemic. There was no serious and death cases on the basis of active treatment on the affected patients. Conclusions: The outbreak of mycoplasma pneumoniae pneumonia often occur in crowded places. And the clinical and imaging features of mycoplasma pneumoniae pneumonia are atypical. Standard epidemiological intervention should be adopted for the sudden onset of respiratory diseases with unknown causes.

WW domain-mediated regulation and activation of E3 ubiquitin ligase Suppressor of Deltex

The Nedd4 family E3 ligases Itch and WWP1/2 play crucial roles in the regulation of cell cycle progression and apoptosis and are closely correlated with cancer development and metastasis. It has been recently shown that the ligase activities of Itch and WWP1/2 are tightly regulated, with the HECT domain sequestered intramolecularly by a linker region connecting WW2 and WW3. Here, we show that a similar autoinhibitory mechanism is utilized by the Drosophila ortholog of Itch and WWP1/2, Suppressor of Deltex (Su(dx)). We show that Su(dx) adopts an inactive steady state with the WW domain region interacting with the HECT domain. We demonstrate that both the linker and preceding WW2 are required for the efficient binding and regulation of Su(dx) HECT. Recruiting the multiple-PY motif-containing adaptor dNdfip via WW domains relieves the inhibitory state of Su(dx) and leads to substrate (e.g. Notch) ubiquitination. Our study demonstrates an evolutionarily conservative mechanism governing the regulation and activation of some Nedd4 family E3 ligases. Our results also suggest a dual regulatory mechanism for specific Notch down-regulation via dNdfip-Su(dx)-mediated Notch ubiquitination.

Differentiation of Alzheimer's disease based on local and global parameters in personalized Virtual Brain models

Alzheimer's disease (AD) is marked by cognitive dysfunction emerging from neuropathological processes impacting brain function. AD affects brain dynamics at the local level, such as changes in the balance of inhibitory and excitatory neuronal populations, as well as long-range changes to the global network. Individual differences in these changes as they relate to behaviour are poorly understood. Here, we use a multi-scale neurophysiological model, “The Virtual Brain (TVB)”, based on empirical multi-modal neuroimaging data, to study how local and global dynamics correlate with individual differences in cognition. In particular, we modeled individual resting-state functional activity of 124 individuals across the behavioural spectrum from healthy aging, to amnesic Mild Cognitive Impairment (MCI), to AD. The model parameters required to accurately simulate empirical functional brain imaging data correlated significantly with cognition, and exceeded the predictive capacity of empirical connectomes.

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Modeled local and global dynamics correlate with individual cognition in Alzheimer's.

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Proof of concept of The Virtual Brain to characterize individual dynamics

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Brain-behaviour relations depend on the network modeled (whole brain or limbic).

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Model parameters predict cognition better than metrics of neuroimaging data.

Structural determinants controlling 14-3-3 recruitment to the endocytic adaptor Numb and dissociation of the Numb·α-adaptin complex

Traffic of cargo across membranes helps establish, maintain, and reorganize distinct cellular compartments and is fundamental to many metabolic processes. The cargo-selective endocytic adaptor Numb participates in clathrin-dependent endocytosis by attaching cargoes to the clathrin adaptor α-adaptin. The phosphorylation of Numb at Ser²⁶⁵ and Ser²⁸⁴ recruits the regulatory protein 14-3-3, accompanied by the dissociation of Numb from α-adaptin and Numb's translocation from the cortical membrane to the cytosol. However, the molecular mechanisms underlying the Numb-α-adaptin interaction and its regulation by Numb phosphorylation and 14-3-3 recruitment remain poorly understood. Here, biochemical and structural analyses of the Numb·14-3-3 complex revealed that Numb phosphorylation at both Ser²⁶⁵ and Ser²⁸⁴ is required for Numb's efficient interaction with 14-3-3. We also discovered that an RQFRF motif surrounding Ser²⁶⁵ in Numb functions together with the canonical C-terminal DPF motif, required for Numb's interaction with α-adaptin, to form a stable complex with α-adaptin. Of note, we provide evidence that the phosphorylation-induced binding of 14-3-3 to Numb directly competes with the binding of α-adaptin to Numb. Our findings suggest a potential mechanism governing the dynamic assembly of Numb with α-adaptin or 14-3-3. This dual-site recognition of Numb by α-adaptin may have implications for other α-adaptin targets. We propose that the newly identified α-adaptin-binding site surrounding Ser²⁶⁵ in Numb functions as a triggering mechanism for the dynamic dissociation of the Numb·α-adaptin complex.

Protein Complex Assemblies in Epithelial Cell Polarity and Asymmetric Cell Division

Asymmetric local concentration of protein complexes on distinct membrane regions is a fundamental property in numerous biological processes and is a hallmark of cell polarity. Evolutionarily conserved core polarity proteins form specific and dynamic networks to regulate the establishment and maintenance of cell polarity, as well as distinct polarity-driven cellular events. This review focuses on the molecular and structural basis governing regulated formation of several sets of core cell polarity regulatory complexes, as well as their functions in epithelial cell polarization and asymmetric cell division.

Modelling and simulation of flow and agglomeration in deep veins valves using discrete multi physics

The hemodynamics in flexible deep veins valves is modelled by means of discrete multi-physics and an agglomeration algorithm is implemented to account for blood accrual in the flow. Computer simulations of a number of valves typologies are carried out. The results show that the rigidity and the length of the valve leaflets play a crucial role on both mechanical stress and stagnation in the flow. Rigid and short membranes may be inefficient in preventing blood reflux, but reduce the volume of stagnant blood potentially lowering the chances of thrombosis. Additionally, we also show that in venous valves, cell agglomeration is driven by stagnation rather than mechanical stress.