[Constructing an early-warning model for mortality risk in heat stroke patients based on Fisher discriminant analysis]

Objective: To establish an early warning model to assess the mortality risk of patients with heat stroke disease. Methods: The case data of patients diagnosed with heat stroke disease admitted to the comprehensive ICU of Shanshan County from January 2016 to December 2020 were selected. According to the short-term outcome (28 days) of patients, they were divided into death group (20 cases) and survival group (53 cases) . The relevant indicators with statistically significant differences between groups within 24 hours after admission were selected. By drawing the subject work curve (ROC) and calculating the area under the curve, the relevant indicators with the area under the curve greater than 0.7 were selected, Fisher discriminant analysis was used to establish an assessment model for the death risk of heat stroke disease. The data of heat stroke patients from January 1, 2021 to December 2022 in the comprehensive ICU of Shanshan County were collected for external verification. Results There were significant differences in age, cystatin C, procalcitonin, platelet count, CKMB, CK, CREA, PT, TT, APTT, heart rate, respiratory rate and GLS score among the groups. Cystatin C, CKMB, CREA, PT, TT, heart rate AUC area at admission was greater than 0.7. Fisher analysis method is used to build a functional model. Results: The diagnostic sensitivity, specificity and AUC area of the functional model were 95%, 83% and 0.937 respectively. The external validation results showed that the accuracy of predicting survival group was 85.71%, the accuracy of predicting death group was 88.89%. Conclusion: The early warning model of heat stroke death constructed by ROC curve analysis and Fisher discriminant analysis can provide objective reference for early intervention of heat stroke.

Stabilizing Supersaturation with Extreme Grain Refinement in Spinodal Aluminum Alloys

Supersaturated solid solutions can be formed in alloys from various non-equilibrium processes, but stabilizing the metastable phases against decomposition is challenging, particularly the spinodal decomposition that occurs via chemical fluctuations without energy barriers to nucleation. In this work, it is found that spinodal decomposition in supersaturated Al(Zn) solid solutions can be inhibited with straining-induced extreme grain refinement. For the refined supersaturated grains at the nanoscale, their spinodal decomposition is obviously resisted by the relaxed grain boundaries and reduced lattice defects. As grains are refined below 10 nm the decomposition is completely inhibited, in which atomic diffusion is blocked by the stable Schwarz crystal structure with vacancy-free grains. Extreme grain refinement offers a general approach to stabilize supersaturated phases with broadened compositional windows for property modulation of alloys.

DNALI1 Promotes Neurodegeneration after Traumatic Brain Injury via Inhibition of Autophagosome-Lysosome Fusion

Traumatic brain injury (TBI) leads to progressive neurodegeneration that may be caused by chronic traumatic encephalopathy (CTE). However, the precise mechanism remains unclear. Herein, the study identifies a crucial protein, axonemal dynein light intermediate polypeptide 1 (DNALI1), and elucidated its potential pathogenic role in post-TBI neurodegeneration. The DNALI1 gene is systematically screened through analyses of Aging, Dementia, and TBI studies, confirming its elevated expression both in vitro and in vivo. Moreover, it is observed that altered DNALI1 expression under normal conditions has no discernible effect. However, upon overexpression, DNALI1 inhibits autophagosome-lysosome fusion, reduces autophagic flux, and exacerbates cell death under pathological conditions. DNALI1 silencing significantly enhances autophagic flux and alleviates neurodegeneration in a CTE model. These findings highlight DNALI1 as a potential key target for preventing TBI-related neurodegeneration.

Pharmacological induction of autophagy reduces inflammation in macrophages by degrading immunoproteasome subunits

Defective autophagy is linked to proinflammatory diseases. However, the mechanisms by which autophagy limits inflammation remain elusive. Here, we found that the pan-FGFR inhibitor LY2874455 efficiently activated autophagy and suppressed expression of proinflammatory factors in macrophages stimulated by lipopolysaccharide (LPS). Multiplex proteomic profiling identified the immunoproteasome, which is a specific isoform of the 20s constitutive proteasome, as a substrate that is degraded by selective autophagy. SQSTM1/p62 was found to be a selective autophagy-related receptor that mediated this degradation. Autophagy deficiency or p62 knockdown blocked the effects of LY2874455, leading to the accumulation of immunoproteasomes and increases in inflammatory reactions. Expression of proinflammatory factors in autophagy-deficient macrophages could be reversed by immunoproteasome inhibitors, confirming the pivotal role of immunoproteasome turnover in the autophagy-mediated suppression on the expression of proinflammatory factors. In mice, LY2874455 protected against LPS-induced acute lung injury and dextran sulfate sodium (DSS)-induced colitis and caused low levels of proinflammatory cytokines and immunoproteasomes. These findings suggested that selective autophagy of the immunoproteasome was a key regulator of signaling via the innate immune system.

Molecular subtype identification and prognosis stratification based on lysosome-related genes in breast cancer

Background

Lysosomes are known to have a significant impact on the development and recurrence of breast cancer. However, the association between lysosome-related genes (LRGs) and breast cancer remains unclear. This study aims to explore the potential role of LRGs in predicting the prognosis and treatment response of breast cancer.

Methods

Breast cancer gene expression profile data and clinical information were downloaded from TCGA and GEO databases, and prognosis-related LRGs were screened for consensus clustering analysis. Lasso Cox regression analysis was used to construct risk features derived from LRGs, and immune cell infiltration, immune therapy response, drug sensitivity, and clinical pathological feature differences were evaluated for different molecular subtypes and risk groups. A nomogram based on risk features derived from LRGs was constructed and evaluated.

Results

Our study identified 176 differentially expressed LRGs that are associated with breast cancer prognosis. Based on these genes, we divided breast cancer into two molecular subtypes with significant prognostic differences. We also found significant differences in immune cell infiltration between these subtypes. Furthermore, we constructed a prognostic risk model consisting of 7 LRGs, which effectively divides breast cancer patients into high-risk and low-risk groups. Patients in the low-risk group have better prognostic characteristics, respond better to immunotherapy, and have lower sensitivity to chemotherapy drugs, indicating that the low-risk group is more likely to benefit from immunotherapy and chemotherapy. Additionally, the risk score based on LRGs is significantly correlated with immune cell infiltration, including CD8 T cells and macrophages. This risk score model, along with age, chemotherapy, clinical stage, and N stage, is an independent prognostic factor for breast cancer. Finally, the nomogram composed of these factors has excellent performance in predicting overall survival of breast cancer.

Conclusions

In conclusion, this study has constructed a novel LRG-derived breast cancer risk feature, which performs well in prognostic prediction when combined with clinical pathological features.

PAK inhibitor FRAX486 decreases the metastatic potential of triple-negative breast cancer cells by blocking autophagy

BACKGROUND

Triple-negative breast cancer (TNBC) is a unique breast cancer subtype with a high risk of metastasis and recurrence and a poor prognosis. Epithelial-mesenchymal transition (EMT) endows epithelial cells with the ability to move to distant sites, which is essential for the metastasis of TNBC to organs, including the lung. Autophagy, an intracellular degradation process that involves formation of double-layered lipid autophagosomes that transport cytosolic cargoes into lysosomes via autophagosome-lysosome fusion, is involved in various diseases, including cancer and neurodegenerative, metabolic, cardiovascular, and infectious diseases. The relationship between autophagy and cancer has become relatively clear. However, research on pharmacological drugs that block cancer EMT by targeting autophagy is still in the initial stages. Therefore, the re-evaluation of old drugs for their potential in blocking both autophagy and EMT was conducted.

METHODS

More than 2000 small molecule chemicals were screened for dual autophagy/EMT inhibitors, and FRAX486 was identified as the best candidate inhibitor of autophagy/EMT. The functions of FRAX486 in TNBC metastasis were detected by CCK-8, migration and wound healing assays. The effects of FRAX486 on autophagy and its target PAK2 were determined by immunoblotting, immunofluorescence, immunoprecipitation analysis and transmission electron microscopy. The findings were validated in mouse models.

RESULTS

Here, we report that FRAX486, a potent P21-activated kinase 2 (PAK2) inhibitor, facilitates TNBC suppression both in vitro and in vivo by blocking autophagy. Mechanistically, FRAX486 inhibits autophagy in TNBC cells by targeting PAK2, leading to the ubiquitination and proteasomal degradation of STX17, which mediates autophagosome-lysosome fusion. The inhibition of autophagy by FRAX486 causes upregulation of the epithelial marker protein E-cadherin and thus suppresses the migration and metastasis of TNBC cells.

CONCLUSIONS

The effects of FRAX486 on TNBC metastasis suppression were verified to be dependent on PAK2 and autophagy inhibition. Together, our results provide a molecular basis for the application of FRAX486 as a potential treatment for inhibiting the metastasis of TNBC.

Vegetation-fire feedbacks increase subtropical wildfire risk in scrubland and reduce it in forests

Climate dictates wildfire activity around the world. But East and Southeast Asia are an apparent exception as fire-activity variation there is unrelated to climatic variables. In subtropical China, fire activity decreased by 80% between 2003 and 2020 amid increased fire risks globally. Here, we assessed the fire regime, vegetation structure, fuel flammability and their interactions across subtropical Hubei, China. We show that tree basal area (TBA) and fuel flammability explained 60% of fire-frequency variance. Fire frequency and fuel flammability, in turn, explained 90% of TBA variance. These results reveal a novel system of scrubland-forest stabilized by vegetation-fire feedbacks. Frequent fires promote the persistence of derelict scrubland through positive vegetation-fire feedbacks; in forest, vegetation-fire feedbacks are negative and suppress fire. Thus, we attribute the decrease in wildfire activity to reforestation programs that concurrently increase forest coverage and foster negative vegetation-fire feedbacks that suppress wildfire.

ALS-linked C9orf72-SMCR8 complex is a negative regulator of primary ciliogenesis

Massive GGGGCC (G4C2) repeat expansion in C9orf72 and the resulting loss of C9orf72 function are the key features of ~50% of inherited amyotrophic lateral sclerosis and frontotemporal dementia cases. However, the biological function of C9orf72 remains unclear. We previously found that C9orf72 can form a stable GTPase activating protein (GAP) complex with SMCR8 (Smith-Magenis chromosome region 8). Herein, we report that the C9orf72-SMCR8 complex is a major negative regulator of primary ciliogenesis, abnormalities in which lead to ciliopathies. Mechanistically, the C9orf72-SMCR8 complex suppresses the primary cilium as a RAB8A GAP. Moreover, based on biochemical analysis, we found that C9orf72 is the RAB8A binding subunit and that SMCR8 is the GAP subunit in the complex. We further found that the C9orf72-SMCR8 complex suppressed the primary cilium in multiple tissues from mice, including but not limited to the brain, kidney, and spleen. Importantly, cells with C9orf72 or SMCR8 knocked out were more sensitive to hedgehog signaling. These results reveal the unexpected impact of C9orf72 on primary ciliogenesis and elucidate the pathogenesis of diseases caused by the loss of C9orf72 function.

Palmitoylated Sept8-204 modulates learning and anxiety by regulating filopodia arborization and actin dynamics

Septin proteins are involved in diverse physiological functions, including the formation of specialized cytoskeletal structures. Septin 8 (Sept8) is implicated in spine morphogenesis and dendritic branching through palmitoylation. We explored the role and regulation of a Sept8 variant in human neural-like cells and in the mouse brain. We identified Sept8-204 as a brain-specific variant of Sept8 that was abundant in neurons and modified by palmitoylation, specifically at Cys469, Cys470, and Cys472. Sept8-204 palmitoylation was mediated by the palmitoyltransferase ZDHHC7 and was removed by the depalmitoylase PPT1. Palmitoylation of Sept8-204 bound to F-actin and induced cytoskeletal dynamics to promote the outgrowth of filopodia in N2a cells and the arborization of neurites in hippocampal neurons. In contrast, a Sept8-204 variant that could not be palmitoylated because of mutation of all three Cys residues (Sept8-204-3CA) lost its ability to bind F-actin, and expression of this mutant did not promote morphological changes. Genetic deletion of Sept8, Sept8-204, or Zdhhc7 caused deficits in learning and memory and promoted anxiety-like behaviors in mice. Our findings provide greater insight into the regulation of Sept8-204 by palmitoylation and its role in neuronal morphology and function in relation to cognition.

Autophagy is regulated by endoplasmic reticulum calcium homeostasis and sphingolipid metabolism

Calcium is involved in a variety of cellular processes. As the crucial components of cell membranes, sphingolipids also play important roles as signaling molecules. Intracellular calcium homeostasis, autophagy initiation and sphingolipid synthesis are associated with the endoplasmic reticulum (ER). Recently, through genetic screening and lipidomics analysis in Saccharomyces cerevisiae, we found that the ER calcium channel Csg2 converts sphingolipid metabolism into macroautophagy/autophagy regulation by controlling ER calcium homeostasis. The results showed that Csg2 acts as a calcium channel to mediate ER calcium efflux into the cytoplasm, and deletion of CSG2 causes a distinct increase of ER calcium concentration, thereby disrupting the stability of the sphingolipid synthase Aur1, leading to the accumulation of the bioactive sphingolipid phytosphingosine (PHS), which specifically and completely blocks autophagy. In summary, our work links calcium homeostasis, sphingolipid metabolism, and autophagy initiation via the ER calcium channel Csg2.

The impact of acute-phase reaction on mortality and re-fracture after zoledronic acid in hospitalized elderly osteoporotic fracture patients

This study involving 674 elderly osteoporotic fracture (OPF) patients undergoing orthopedic surgery investigated the long-term outcomes of acute phase reaction (APR) after initial zoledronic acid (ZOL). Those who had an APR had a 97% higher risk of mortality and a 73% lower rate of re-fracture than patients who did not.

INTRODUCTION

Annual infusion of ZOL efficiently decreases the risk of fracture. A temporary APR, consisting of flu-like symptoms, myalgia, and fever, is frequently observed within 3 days after the first dose. This work aimed to identify whether the occurrence of APR after initial ZOL infusion is a reliable indicator of drug efficacy for mortality and re-fracture in elderly OPF patients undergoing orthopedic surgery.

METHODS

This retrospectively observed work was constructed on a database prospectively collected from the Osteoporotic Fracture Registry System of a tertiary level A hospital in China. Six hundred seventy-four patients 50 years old or older with newly identified hip/morphological vertebral OPF who received ZOL for the first time after orthopedic surgery were included in the final analysis. APR was identified as a maximum axillary body temperature greater than 37.3 °C for the first 3 days after ZOL infusion. We utilized models of multivariate Cox proportional hazards to compare the risk of all-cause mortality in OPF patients with APR (APR+) and without APR (APR-). Competing risks regression analysis was used to examine the association between the occurrence of APR and re-fracture when mortality was taken into account.

RESULTS

In a fully adjusted Cox proportional hazards model, APR+ patients had a significantly higher risk of death than APR- patients with a hazard ratio [HR] 1.97 (95% CI, 1.09-3.56; P-value = 0.02). Furthermore, in an adjusted competing risk regression analysis, APR+ patients had a significantly reduced risk of re-fracture compared with APR- patients with a sub-distribution HR, 0.27 (95% CI, 0.11-0.70; P-value = 0.007).

CONCLUSIONS

Our findings suggested a potential association between the occurrence of APR and increased mortality risk. An initial dose of ZOL following orthopedic surgery was found to be protective against re-fracture in older patients with OPFs.

[Efficacy and safety of bendamustine-rituximab combination therapy for newly diagnosed indolent B-cell non-Hodgkin's lymphoma and elderly mantle cell lymphoma: a multi-center prospective phase II clinical trial in China]

Objectives: This study aimed to assess the efficacy and safety of bendamustine in combination with rituximab (BR regimen) for the treatment of newly diagnosed indolent B-cell non-Hodgkin's lymphoma (B-iNHL) and elderly mantle cell lymphoma (eMCL) . Methods: From December 1, 2020 to September 10, 2022, a multi-center prospective study was conducted across ten Grade A tertiary hospitals in Shandong Province, China. The BR regimen was administered to evaluate its efficacy and safety in newly diagnosed B-iNHL and eMCL patients, and all completed at least four cycles of induction therapy. Results: The 72 enrolled patients with B-iNHL or MCL were aged 24-74 years, with a median age of 55 years. Eastern Cooperative Oncology Group (ECOG) performance status scores of 0-1 were observed in 76.4% of patients, while 23.6% had scores of 2. Disease distribution included follicular lymphoma (FL) (51.4% ), marginal zone lymphoma (MZL) (33.3% ), eMCL (11.1% ), and the unknown subtype (4.2% ). According to the Ann Arbor staging system, 16.7% and 65.3% of patients were diagnosed with stage Ⅲ and stage Ⅳ lymphomas, respectively. Following four cycles of BR induction therapy, the overall response rate was 98.6%, with a complete response (CR) rate of 83.3% and a partial response (PR) rate of 15.3%. Only one eMCL patient experienced disease progression during treatment, and only one FL patient experienced a relapse. Even when evaluated using CT alone, the CR rate was 63.9%, considering the differences between PET/CT and CT assessments. The median follow-up duration was 11 months (range: 4-22), with a PFS rate of 96.8% and an OS rate of 100.0%. The main hematologic adverse reactions included grade 3-4 leukopenia (27.8%, with febrile neutropenia observed in 8.3% of patients), grade 3-4 lymphopenia (23.6% ), grade 3-4 anemia (5.6% ), and grade 3-4 thrombocytopenia (4.2% ). The main non-hematologic adverse reactions such as fatigue, nausea/vomiting, rash, and infections occurred in less than 20.0% of patients. Conclusion: Within the scope of this clinical trial conducted in China, the BR regimen demonstrated efficacy and safety in treating newly diagnosed B-iNHL and eMCL patients.

The ER calcium channel Csg2 integrates sphingolipid metabolism with autophagy

Sphingolipids are ubiquitous components of membranes and function as bioactive lipid signaling molecules. Here, through genetic screening and lipidomics analyses, we find that the endoplasmic reticulum (ER) calcium channel Csg2 integrates sphingolipid metabolism with autophagy by regulating ER calcium homeostasis in the yeast Saccharomyces cerevisiae. Csg2 functions as a calcium release channel and maintains calcium homeostasis in the ER, which enables normal functioning of the essential sphingolipid synthase Aur1. Under starvation conditions, deletion of Csg2 causes increases in calcium levels in the ER and then disturbs Aur1 stability, leading to accumulation of the bioactive sphingolipid phytosphingosine, which specifically and completely blocks autophagy and induces loss of starvation resistance in cells. Our findings indicate that calcium homeostasis in the ER mediated by the channel Csg2 translates sphingolipid metabolism into autophagy regulation, further supporting the role of the ER as a signaling hub for calcium homeostasis, sphingolipid metabolism and autophagy.

Transcriptional regulation of autophagy by RNA polymerase II

Macroautophagy/autophagy is a catabolic recycling pathway and is tightly regulated by upstream signals. Autophagy genes are quickly upregulated upon stimuli such as nutrition limitation in response to the external environment. However, how the transcriptional activation of autophagy genes occurs is not well understood. We recently found that in yeast, the RNA polymerase II subunit Rpb9 specifically and efficiently upregulates the transcription of the autophagy gene ATG1 with the mediation of Gcn4. Such regulation was shown to be essential for autophagic activities induced by starvation. Furthermore, the function of Rpb9 in autophagy and the activation of ATG1 transcription is conserved in mammalian cells. In conclusion, Rpb9 specifically and positively regulates ATG1 transcription as a key regulator of autophagy.

Modular characterization of SARS-CoV-2 nucleocapsid protein domain functions in nucleocapsid-like assembly

SARS-CoV-2 and its variants, with the Omicron subvariant XBB currently prevailing the global infections, continue to pose threats on public health worldwide. This non-segmented positive-stranded RNA virus encodes the multi-functional nucleocapsid protein (N) that plays key roles in viral infection, replication, genome packaging and budding. N protein consists of two structural domains, NTD and CTD, and three intrinsically disordered regions (IDRs) including the N_IDR, the serine/arginine rich motif (SR_IDR), and the C_IDR. Previous studies revealed functions of N protein in RNA binding, oligomerization, and liquid-liquid phase separation (LLPS), however, characterizations of individual domains and their dissected contributions to N protein functions remain incomplete. In particular, little is known about N protein assembly that may play essential roles in viral replication and genome packing. Here, we present a modular approach to dissect functional roles of individual domains in SARS-CoV-2 N protein that reveals inhibitory or augmented modulations of protein assembly and LLPS in the presence of viral RNAs. Intriguingly, full-length N protein (N_FL) assembles into ring-like architecture whereas the truncated SR_IDR-CTD-C_IDR (N_182-419) promotes filamentous assembly. Moreover, LLPS droplets of N_FL and N_182-419 are significantly enlarged in the presence of viral RNAs, and we observed filamentous structures in the N_182-419 droplets using correlative light and electron microscopy (CLEM), suggesting that the formation of LLPS droplets may promote higher-order assembly of N protein for transcription, replication and packaging. Together this study expands our understanding of the multiple functions of N protein in SARS-CoV-2.

Risk factors for the development of severe breast cancer-related lymphedema: a retrospective cohort study

BACKGROUND

Severe lymphedema presents a challenge in terms of treatment due to the significant formation of scar tissue that accompanies it. The aim of this study was to identify intraoperative and preoperative risk factors of severe lymphedema and to develop a nomogram for estimating the risk of severe lymphedema within 3 years of surgery.

METHOD

Data was collected from a retrospective cohort of 326 patients with BCRL at the Zhejiang Cancer Hospital from November 2015 to November 2018. Univariate and multivariate logistic regression analysis was conducted to identify predictive indicators of severe lymphedema. A nomogram was developed to further improve the clinical applicability.

RESULTS

In the retrospective cohort, the ratio of severe/non-severe lymphedema within 3 years of surgery was 1:3. Independent risk factors for severe lymphedema were determined to be age, positive lymph nodes, interpectoral (Rotter's) lymph nodes (IPNs) dissection, and educational level. IPNs dissection was found to contribute greatly to the development of severe lymphedema with a higher odds ratio (7.76; 95% CI: 3.87-15.54) than other risk factors. A nomogram was developed by integrating age, positive lymph nodes, IPNs dissection, and educational level, which yielded a C-index of 0.810 and 0.681 in the training and validation cohort, respectively. This suggested a moderate performance of the nomogram in predicting the risk of severe lymphedema within 3 years of surgery. The cut-off values of the low-, medium- and high-risk probabilities were 0.0876 and 0.3498, and the severe lymphedema exhibited a significantly higher risk probability as compared with the non-severe lymphedema.

CONCLUSION

This study identified the risk factors of severe lymphedema and highlighted the substantial contribution of IPNs dissection to the severity of lymphedema.

Lipid phosphatase SAC1 suppresses hepatitis B virus replication through promoting autophagic degradation of virions

Phosphatidylinositol lipids play vital roles in lipid signal transduction, membrane recognition, vesicle transport, and viral replication. Previous studies have revealed that SAC1-like phosphatidylinositol phosphatase (SACM1L/SAC1), which uses phosphatidylinositol-4-phosphate (PI4P) as its substrate, greatly affects the replication of certain bacteria and viruses in vitro. However, it remains unclear whether and how SAC1 modulates hepatitis B virus (HBV) replication in vitro and in vivo. In the present study, we observed that SAC1 silencing significantly increased HBV DNA replication, subviral particle (SVP) expression, and secretion of HBV virions, whereas SAC1 overexpression exerted the opposite effects. Moreover, SAC1 overexpression inhibited HBV DNA replication and SVP expression in a hydrodynamic injection-based HBV-persistent replicating mouse model. Mechanistically, SAC1 silencing increased the number of HBV-containing autophagosomes as well as PI4P levels on the autophagosome membrane. Moreover, SAC1 silencing blocked autophagosome-lysosome fusion by inhibiting the interaction between synaptosomal-associated protein 29 and vesicle-associated membrane protein 8. Collectively, our data indicate that SAC1 significantly inhibits HBV replication by promoting the autophagic degradation of HBV virions. Our findings support that SAC1-mediated phospholipid metabolism greatly modulates certain steps of the HBV life-cycle and provide a new theoretical basis for antiviral therapy.

Autophagy: Dual roles and perspective for clinical treatment of colorectal cancer

Colorectal cancer (CRC) raises concerns to people because of its high recurrence and metastasis rate, diagnosis challenges, and poor prognosis. Various studies have shown the association of altered autophagy with tumorigenesis, tumor-stroma interactions, and resistance to cancer therapy in CRC. Autophagy is a highly conserved cytosolic catabolic process in eukaryotes that plays distinct roles in CRC occurrence and progression. In early tumorigenesis, autophagy may inhibit tumor growth through diverse mechanisms, whereas it exhibits a tumor promoting function in CRC progression. This different functions of autophagy in CRC occurrence and progression make developing therapies targeting autophagy complicated. In this review, we discuss the classification and process of autophagy as well as its dual roles in CRC, functions in the tumor microenvironment, cross-talk with apoptosis, and potential usefulness as a CRC therapeutic target.

Inhibiting creep in nanograined alloys with stable grain boundary networks

Creep, the time-dependent deformation of materials stressed below the yield strength, is responsible for a great number of component failures at high temperatures. Because grain boundaries (GBs) in materials usually facilitate diffusional processes in creep, eliminating GBs is a primary approach to resisting high-temperature creep in metals, such as in single-crystal superalloy turbo blades. We report a different strategy to inhibiting creep by use of stable GB networks. Plastic deformation triggered structural relaxation of high-density GBs in nanograined single-phased nickel-cobalt-chromium alloys, forming networks of stable GBs interlocked with abundant twin boundaries. The stable GB networks effectively inhibit diffusional creep processes at high temperatures. We obtained an unprecedented creep resistance, with creep rates of ~10 –7 per second under gigapascal stress at 700°C (~61% melting point), outperforming that of conventional superalloys.

The RNA polymerase II subunit Rpb9 activates ATG1 transcription and autophagy

Macroautophagy/autophagy is a conserved process in eukaryotic cells that mediates the degradation and recycling of intracellular substrates. Proteins encoded by autophagy-related (ATG) genes are essentially involved in the autophagy process and must be tightly regulated in response to various circumstances, such as nutrient-rich and starvation conditions. However, crucial transcriptional activators of ATG genes have remained obscure. Here, we identify the RNA polymerase II subunit Rpb9 as an essential regulator of autophagy by a high-throughput screen of a Saccharomyces cerevisiae gene knockout library. Rpb9 plays a crucial and specific role in upregulating ATG1 transcription, and its deficiency decreases autophagic activities. Rpb9 promotes ATG1 transcription by binding to its promoter region, which is mediated by Gcn4. Furthermore, the function of Rpb9 in autophagy and its regulation of ATG1/ULK1 transcription are conserved in mammalian cells. Together, our results indicate that Rpb9 specifically activates ATG1 transcription and thus positively regulates the autophagy process.

Chronic insulin resistance deteriorates cardiac mitochondrial quality control in a mouse model of SEC-NAFLD-IR

Background

Insulin resistance and nonalcoholic fatty liver disease (NAFLD) both relate to cardiovascular mortality. Using a mouse model of chronic lipid overload and secondary-NAFLD-induced insulin resistance (SEC-NAFLD-IR), we recently deciphered that SEC-NAFLD-IR already at young age provoked myocardial lipotoxicity with reduced mitochondrial efficiency and increased vulnerability to cardiac ischemia. However, long-term consequences of SEC-NAFLD-IR remain elusive.

Purpose

Here we aimed to elucidate the impact of long-term SEC-NAFLD-IR on multiple mitochondrial quality control (mQC) mechanisms in the heart and its consequences for cardiac function.

Methods

We studied 36 SEC-NAFLD-IR mice (72-week-old). For mechanistic experiments, we applied palmitate-induced insulin resistant murine HL-1 cells. Cardiac mitochondrial dynamics were measured via quantification of mitochondrial morphology and expression of mitochondrial fusion and fission factors (Opa1, Drp1, Fis1, Mfn 1 & 2). Mitophagy level was evaluated via immunofluorescence and protein expression of key mitophagy-related genes (Parkin, NIX, LC3). Mitochondrial biogenesis and mass were examined via quantitation of PGC-1α expression, mtDNA and citrate synthase activity.

Results

72-week-old SEC-NAFLD-IR mice exhibited 21% (p=0.001) and 32% (p<0.001) higher body weight and heart weight compared with controls. Along with elevated oxidative stress, hepatic lipid accumulation and inflammation, 6h-fasted SEC-NAFLD-IR mice were characterized by increased plasma glucose, insulin and cholesterol. SEC-NAFLD-IR mice displayed a cardiac phenotype with 21% higher left ventricular mass (normalized to body weight, p<0.001) and 6% lower ejection fraction compared to controls (73.5% SEM 0.90 vs 69.4% SEM 1.65, p=0.04). We found several advantageous mQC mechanisms suppressed in aged SEC-NAFLD-IR mice including long form OPA1-mediated mitochondrial fusion, Parkin- and NIX-mediated mitophagy. Likewise, mitochondrial biogenesis was suppressed in the aged insulin-resistant heart, which was connected to a 65% downregulation of PGC-1α1 expression (p=0.01). Interestingly, downregulation of cardiac PGC-1α1 in aged SEC-NAFLD-IR mice coincided with upregulation of PARIS, indicating the crucial participation of the Parkin/PARIS pathway in mQC of the insulin-resistant heart. In addition, induction of insulin resistance in murine HL-1 cardiomyocytes also led to increased mitochondrial fragmentation and decreased PGC-1α1 expression.

Conclusion

This study demonstrated that regulation of mitochondrial network and turnover is hampered by SEC-NAFLD-IR in the hearts of aged mice, which may contribute to hypertrophy and cardiac dysfunction in insulin resistance.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Collaborative Research Centre 1116 (German Research Foundation)

Case report: Ultrasound-Assisted endovascular therapy for carotid artery floating thrombus

Background

Carotid free-floating thrombus (CFFT) is a rare but sometimes emergent condition. There has been controversy over the optimal treatment strategy. Emerging evidence suggests that endovascular thrombectomy (EVT) may be an alternative to surgery. Accurate alignment of the aspiration catheter and thrombus during EVT is critical but has, so far, remained unresolved.

Case summary

This is a rare case of CFFT presenting with acute right-sided facial droop and moderate dysarthria in a 77-year-old man. He was in sinus rhythm with a blood pressure of 110/82 mmHg. Both non-contrast CT (NCCT) and head CT angiography (CTA) were unremarkable, while whole-brain CT perfusion (WB-CTP) suggested left hemisphere core infarction. Delayed imaging of the left internal carotid system by 4D-CTA suggested severe proximal obstructive disease, as confirmed by carotid CTA and ultrasonography. The initial two aspirations under DSA were invalid due to the challenging anatomical angle between the thrombus and the catheter. The success of CFFT removal was achieved with a pressure-assisted ultrasound-guided approach that helps to compress the catheter tip toward the thrombus.

Conclusion

We innovatively report a successful ultrasound-guided EVT for CFFT. Ultrasound assistance can provide quick and effective guidance and may guide tailored aspirations during EVT.

Cleavage of the selective autophagy receptor SQSTM1/p62 by the SARS-CoV-2 main protease NSP5 prevents the autophagic degradation of viral membrane proteins

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the coronavirus disease 2019 (COVID-19) global pandemic. Omicron, a new variant of SARS-CoV-2, has the characteristics of strong transmission and pathogenicity, short incubation period, and rapid onset progression, and has spread rapidly around the world. The high replication rate and intracellular accumulation of SARS-CoV-2 are remarkable, but the underlying molecular mechanisms remain unclear. Autophagy acts as a conservative cellular defence mechanism against invading pathogens. Here, we provide evidence that the main protease of SARS-CoV-2, NSP5, effectively cleaves the selective autophagy receptor p62. NSP5 targets p62 for cleavage at glutamic acid 354 and thus abolishes the capacity of p62 to mediate selective autophagy. It was further shown that p62 specifically interacted with ubiquitinated SARS-CoV-2 M, the viral membrane protein, to promote its autophagic degradation. In the presence of NSP5, p62-mediated autophagic degradation of the M protein was inhibited. The cleaved products of p62 also cannot facilitate the degradation of the M protein. Collectively, our findings reveal that p62 is a novel host target of SARS-CoV-2 NSP5 and suggest that selective autophagy targets viruses and potential strategies by which the virus evades autophagic clearance. Our results may provide new ideas for the development of anti-COVID-19 drugs based on autophagy and NSP5.

Clinical Experience of Diagnosis and Surgical Treatment of 6 Cases of Acute Subhepatic Appendicitis

To summarize the experience of diagnosis and surgical treatment of 6 cases of acute subhepatic appendicitis. The clinical data of 6 patients with subacute appendicitis in Zhejiang Provincial People's Hospital from July 2018 to December 2019 were analyzed retrospectively. Results. There were 5 males and 1 female. All 6 cases were diagnosed as appendicitis by abdominal CT before operation. All patients underwent laparoscopic appendectomy without conversion to laparotomy. One case of ectopic appendix was located under the liver with absence of ascending colon, one case of ectopic appendix was located under the liver with ectopic ascending colon of transverse colon, one case of appendix head was located in the liver cyst, and the resection of liver cyst was performed at the same time, and three cases of retrocolonic appendix head were located under the liver. Postoperative pathology confirmed appendicitis. For patients with right upper abdominal pain and tenderness, the possibility of subhepatic appendicitis should be considered before operation. Emergency abdominal CT has more advantages than ultrasound. Laparoscopy can not only make a definite diagnosis but also perform appendectomy at the same time.

Protocol to quantify palmitoylation of cysteines in budding yeast

Palmitoylation is a special kind of lipid modification that targets proteins to membranes. This protocol introduces the acyl-biotin exchange (ABE) assay to determine the palmitoylation of protein cysteines in yeast. Palmitoylation is exchanged by biotinylated compounds so that the palmitoyl proteins can be affinity-purified for downstream assay by western blot. This protocol is easy to perform and can be applied to other biological sources with slight modifications. This protocol is limited to the detection of cysteine-based palmitoylation. For complete details on the use and execution of this profile, please refer to Lei et al. (2021).

N-terminal acetylation regulates autophagy

Posttranslational modification (PTM) is pivotal for regulating protein functions. Compared to acetylation on lysine residues, the functions and molecular mechanisms of N-terminal acetylation that occur on the first amino acids of proteins are less understood in the macroautophagy/autophagy field. We recently demonstrated that the B-type N-terminal acetyltransferase NatB, formed by the catalytic subunit Nat3 and auxiliary subunit Mdm20, is essential for autophagy. Deficiency of NatB causes blockage of autophagosome formation. We further identified the actin cytoskeleton constituent Act1 and dynamin-like GTPase Vps1 as substrates modified by NatB. The N-terminal acetylation of Act1 promotes its formation of actin filaments and thus facilitates trafficking of Atg9-containing vesicles for autophagosome formation, whereas N-terminal acetylation of Vps1 promotes its interaction with SNARE proteins and facilitates autophagosome-vacuole fusion. Restoring the N-terminal acetylation of Act and Vps1 does not restore autophagy in NatB-deleted cells, suggesting that additional substrates of NatB modification are involved in autophagy regulation.

Experimental Evidence of Intrinsic Current Generation by Turbulence in Stationary Tokamak Plasmas

High-β_{θe} (a ratio of the electron thermal pressure to the poloidal magnetic pressure) steady-state long-pulse plasmas with steep central electron temperature gradient are achieved in the Experimental Advanced Superconducting Tokamak. An intrinsic current is observed to be modulated by turbulence driven by the electron temperature gradient. This turbulent current is generated in the countercurrent direction and can reach a maximum ratio of 25% of the bootstrap current. Gyrokinetic simulations and experimental observations indicate that the turbulence is the electron temperature gradient mode (ETG). The dominant mechanism for the turbulent current generation is due to the divergence of ETG-driven residual flux of current. Good agreement has been found between experiments and theory for the critical value of the electron temperature gradient triggering ETG and for the level of the turbulent current. The maximum values of turbulent current and electron temperature gradient lead to the destabilization of an m/n=1/1 kink mode, which by counteraction reduces the turbulence level (m and n are the poloidal and toroidal mode number, respectively). These observations suggest that the self-regulation system including turbulence, turbulent current, and kink mode is a contributing mechanism for sustaining the steady-state long-pulse high-β_{θe} regime.

Real-world circulating tumor DNA analysis depicts resistance mechanism and clonal evolution in ALK inhibitor-treated lung adenocarcinoma patients

Background

Sequential treatment with different generations of anaplastic lymphoma kinase (ALK) inhibitors have been widely applied to ALK-positive lung cancer; however, resistance mutations inevitably developed. Further characterization of ALK resistance mutations may provide key guidance to subsequent therapies. Here we explored the emergence of secondary ALK mutations during sequential ALK tyrosine kinase inhibitor (TKI) treatment in a real-world study of Chinese lung adenocarcinoma (ADC) patients.

Methods

A clinical-genomic database was queried for lung ADC patients with at least one ALK inhibitor treatment and at least one plasma sample collected following ALK inhibitor treatment. Targeted genome profiling was performed with a 139-gene panel in baseline tumor tissue and serial plasma samples of patients.

Results

A total of 116 patients met inclusion criteria. ALK G1202R was more common in patients with echinoderm microtubule-associated protein-like 4 (EML4)-ALK v3 fusion, whereas ALK L1196M was more common in v1. TP53 mutant patients were significantly associated with harboring multiple ALK resistance mutations (P = 0.03) and v3+/TP53 mutant patients had the highest rate of multiple ALK resistance mutations. The sequential use of ALK TKI led to an increased incidence of concurrent ALK mutations along the lines of therapies. Alectinib had a lower rate (9%) harboring ALK resistance mutation as first-line ALK TKI compared with crizotinib (36%). ALK compound mutations identified included ALK D1203N/L1196M, ALK G1202R/L1196M, and ALK G1202R/F1174C, which may be lorlatinib resistant. Using paired pretreatment and post-treatment samples, we identified several ALK-independent resistance-related genetic alterations, including PTPRD and CNKN2A/B loss, MYC, MYCN and KRAS amplification, and EGFR^19del.

Conclusions

Sequential postprogression plasma profiling revealed that increased lines of ALK inhibitors can accelerate the accumulation of ALK resistance mutations and may lead to treatment-refractory compound ALK mutations. The selection for optimal first-line TKI is very important to achieve a more efficacious long-term strategy and prevent the emergence of on-target resistance, which may provide guidance for clinical decision making.

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ALK resistance mutations were differentially enriched in the setting of EML4-ALK v1/v3 and TP53 status.

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Serial liquid biopsies NGS depicted accumulation of multiple ALK secondary mutations during sequential ALK treatments.

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Several lorlatinib-resistant ALK compound mutations and ALK-independent resistance genetic alterations were identified.

The progress in C9orf72 research: ALS/FTD pathogenesis, functions and structure

The hexanucleotide repeat (GGGGCC) expansion in C9orf72 is accounted for a large proportion of the genetic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The hypotheses of how the massive G4C2 repeats in C9orf72 destroy the neurons and lead to ALS/FTD are raised and improving. As a multirole player, C9orf72 exerts critical roles in many cellular processes, including autophagy, membrane trafficking, immune response, and so on. Notably, the partners of C9orf72, through which C9orf72 participates in the cell activities, have been identified. Notably, the structures of the C9orf72-SMCR8-WDR41 complex shed light on its activity as GTPase activating proteins (GAP). In this manuscript, we reviewed the latest research progress in the C9orf72-mediated ALS/FTD, the physiological functions of C9orf72, and the putative function models of C9orf72/C9orf72-containing complex.

The interplay between emerging human coronavirus infections and autophagy

ABSTRACT Following outbreaks of severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) in 2002 and 2012, respectively, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the third highly pathogenic emerging human coronavirus (hCoV). SARS-CoV-2 is currently causing the global coronavirus disease 2019 (COVID-19) pandemic. CoV infections in target cells may stimulate the formation of numerous double-membrane autophagosomes and induce autophagy. Several studies provided evidence that hCoV infections are closely related to various cellular aspects associated with autophagy. Autophagy may even promote hCoV infection and replication. However, so far it is unclear how hCoV infections induce autophagy and whether the autophagic machinery is necessary for viral propagation. Here, we summarize the most recent advances concerning the mutual interplay between the autophagic machinery and the three emerging hCoVs, SARS-CoV, MERS-CoV, and SARS-CoV-2 and the model system mouse hepatitis virus. We also discuss the applicability of approved and well-tolerated drugs targeting autophagy as a potential treatment against COVID-19.

Function and molecular mechanism of N-terminal acetylation in autophagy

Acetyl ligation to the amino acids in a protein is an important posttranslational modification. However, in contrast to lysine acetylation, N-terminal acetylation is elusive in terms of its cellular functions. Here, we identify Nat3 as an N-terminal acetyltransferase essential for autophagy, a catabolic pathway for bulk transport and degradation of cytoplasmic components. We identify the actin cytoskeleton constituent Act1 and dynamin-like GTPase Vps1 (vacuolar protein sorting 1) as substrates for Nat3-mediated N-terminal acetylation of the first methionine. Acetylated Act1 forms actin filaments and therefore promotes the transport of Atg9 vesicles for autophagosome formation; acetylated Vps1 recruits and facilitates bundling of the SNARE (soluble N-ethylmaleimide-sensitive factor activating protein receptor) complex for autophagosome fusion with vacuoles. Abolishment of the N-terminal acetylation of Act1 and Vps1 is associated with blockage of upstream and downstream steps of the autophagy process. Therefore, our work shows that protein N-terminal acetylation plays a critical role in controlling autophagy by fine-tuning multiple steps in the process.

A conserved Vac8/ARMC3-PtdIns3K-CI cascade regulates autophagy initiation and functions in spermiogenesis by promoting ribophagy

Macroautophagy/autophagy is special because the double-layer lipid-formed autophagosome is formed by de novo generation. Phosphatidylinositol-3-phosphate (PtdIns3P) produced by class III phosphatidylinositol 3-kinase complex I (PtdIns3K-CI) is an essential source lipid for the formation of autophagosomes. However, how autophagy is initiated is unknown. In other words, the mechanism by which PtdIns3K-CI is recruited to the phagophore assembly site (PAS) to initiate autophagosome formation is unclear. We recently uncovered the pivotal role of yeast Vac8 in autophagy initiation through the recruitment of PtdIns3K-CI to the PAS. N-terminal palmitoylation of Vac8 anchors it to the vacuole membrane, and the middle ARM domains bind PtdIns3K-CI, leading to the generation of PtdIns3P at the PAS and subsequent autophagosome formation. We found that mouse ARMC3 is the homolog of yeast Vac8 and that its autophagic roles are conserved. Interestingly, spermatids from mice with Armc3 deletion showed blocked ribophagy, low energy levels of mitochondria and motionless flagella, which caused male infertility. These findings revealed a germ tissue-specific autophagic function of ARMC3 in complex eukaryotic species.

Butyrate functions in concert with myeloid-derived suppressor cells recruited by CCR9 to alleviate DSS-induced murine colitis

Ulcerative colitis (UC) is a precancerous disease caused mainly by a combination of genetic susceptibility, environmental factors and microbiota dysbiosis. As a kind of short-chain fatty acid (SCFA), butyrate has been shown to be closely related to the progression of colitis. However, the exact regulatory mechanism of butyrate in colitis needs to be further elucidated. In our current research, the effects of butyrate were examined in a dextran sulfate sodium (DSS)-induced murine colitis model, which simulates human UC. The administration of butyrate significantly reversed the signs of colitis and alleviated colonic histological damage in DSS‑induced colitis. The transcription levels of the main proinflammatory mediators, including tumor necrosis factor-α, interleukin-6 and interleukin-12, were also reduced, as determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). This indicates that butyrate could alleviate DSS-induced colitis by inhibiting proinflammatory mediators. In addition, we found that myeloid-derived suppressor cells (MDSCs), which have an inflammation-relieving effect, did not effectively alleviate DSS‑induced colitis but showed a compensatory increase in the DSS group. However, the compensatory increase in MDSCs in the DSS group significantly decreased after butyrate treatment. Moreover, the chemokine receptor CCR9, which mediates the homing of intestinal immune cells, also showed consistent changes similar to MDSCs. Butyrate alone did not have the aforementioned effects on mice. Thus, butyrate may effectively relieve DSS‑induced colitis by synergistic regulatory effects with MDSCs, which migrate and gather through CCR9 recruitment.

Formation of Stable Schwarz Crystals in Polycrystalline Copper at the Grain Size Limit

A prototype Schwarz crystal (SC) structure of dividing-space minimal grain boundaries (GBs) constrained by coherent twin boundaries (CTBs) was recently discovered in extremely fine-grained polycrystalline Cu. In this Letter, constraining effects of 3D CTB network on the formation and thermostability of SC are addressed via atomistic simulations. GB migration and evolution of CTB network trigger formation of SC diamond. CTB constraints are critical to generate GBs of zero mean curvature underlying vanishing capillary pressure, and to counterbalance the elastic driving forces of lattice. GB motion can be suppressed at temperatures close to the melting point with GB aperture down to 3 nm.

Autophagic elimination of ribosomes during spermiogenesis provides energy for flagellar motility

How autophagy initiation is regulated and what the functional significance of this regulation is are unknown. Here, we characterized the role of yeast Vac8 in autophagy initiation through recruitment of PIK3C3-C1 to the phagophore assembly site (PAS). This recruitment is dependent on the palmitoylation of Vac8 and on its middle ARM domains for binding PIK3C3-C1. Vac8-mediated anchoring of PIK3C3-C1 promotes PtdIns3P generation at the PAS and recruitment of the PtdIns3P binding protein Atg18-Atg2. The mouse homolog of Vac8, ARMC3, is conserved and functions in autophagy in mouse testes. Mice lacking ARMC3 have normal viability but show complete male infertility. Proteomic analysis indicated that the autophagic degradation of cytosolic ribosomes was blocked in ARMC3-deficient spermatids, which caused low energy levels of mitochondria and motionless flagella. These studies uncovered a function of Vac8/ARMC3 in PtdIns3-kinase anchoring at the PAS and its physical significance in mammalian spermatogenesis with a germ tissue-specific autophagic function.

Suppressing atomic diffusion with the Schwarz crystal structure in supersaturated Al-Mg alloys

High atomic diffusivity in metals enables substantial tuneability of their structure and properties by tailoring the diffusional processes, but this causes their customized properties to be unstable at elevated temperatures. Eliminating diffusive interfaces by fabricating single crystals or heavily alloying helps to address this issue but does not inhibit atomic diffusion at high homologous temperatures. We discovered that the Schwarz crystal structure was effective at suppressing atomic diffusion in a supersaturated aluminum-magnesium alloy with extremely fine grains. By forming these stable structures, diffusion-controlled intermetallic precipitation from the nanosized grains and their coarsening were inhibited up to the equilibrium melting temperature, around which the apparent across-boundary diffusivity was reduced by about seven orders of magnitude. Developing advanced engineering alloys using the Schwarz crystal structure may lead to useful properties for high-temperature applications.