The Efficacy of Different Material Scaffold-Guided Cell Transplantation in the Treatment of Spinal Cord Injury in Rats: A Systematic Review and Network Meta-analysis.

Cell transplantation is a promising treatment option for spinal cord injury (SCI). However, there is no consensus on the choice of carrier scaffolds to host the cells. This study aims to evaluate the efficacy of different material scaffold-mediated cell transplantation in treating SCI in rats. According to PRISMA's principle, Embase, PubMed, Web of Science, and Cochrane databases were searched, and relevant literature was referenced. Only original research on cell transplantation plus natural or synthetic scaffolds in SCI rats was included. Direct and indirect evidence for improving hind limb motor function was pooled through meta-analysis. A subgroup analysis of some factors that may affect the therapeutic effect was conducted to understand the results fully. In total, 25 studies met the inclusion criteria, in which 293 rats received sham surgery, 78 rats received synthetic material scaffolds, and 219 rats received natural materials scaffolds. The network meta-analysis demonstrated that although synthetic scaffolds were slightly inferior to natural scaffolds in terms of restoring motor function in cell transplantation of SCI rats, no statistical differences were observed between the two (MD: -0.35; 95% CI -2.6 to 1.9). Moreover, the subgroup analysis revealed that the type and number of cells may be important factors in therapeutic efficacy (P < 0.01). Natural scaffolds and synthetic scaffolds are equally effective in cell transplantation of SCI rats without significant differences. In the future, the findings need to be validated in multicenter, large-scale, randomized controlled trials in clinical practice. Trial registration: Registration ID CRD42024459674 (PROSPERO).

Multi-platform omics sequencing dissects the atlas of plasma-derived exosomes in rats with or without depression-like behavior after traumatic spinal cord injury.

BACKGROUND: Exosomes can penetrate the blood-brain barrier for material exchange between the peripheral and central nervous systems. Differences in exosome contents could explain the susceptibility of different individuals to depression-like behavior after traumatic spinal cord injury (TSCI). METHODS: Hierarchical clustering was used to integrate multiple depression-related behavioral outcomes in sham and TSCI rats and ultimately identify non-depressed and depressed rats. The difference in plasma exosome contents between non-depressed and depressed rats after TSCI was assessed in 15 random subjects by performing plasma exosome transcriptomics, mass spectroscope-based proteomics, and non-targeted metabolomics analyses. RESULTS: The results revealed that about 27.6% of the rats developed depression-like behavior after TSCI. Totally, 10 differential metabolites, 81 differentially expressed proteins (DEPs), 373 differentially expressed genes (DEGs), and 55 differentially expressed miRNAs (DEmiRNAs) were identified between non-depressed TSCI and sham rats. Meanwhile, 37 differential metabolites, 499 DEPs, 1361 DEGs, and 89 DEmiRNAs were identified between depressed and non-depressed TSCI rats. Enrichment analysis showed that the progression of depression-like behavior after TSCI may be related to amino acid metabolism disorder and dysfunction of multiple signaling pathways, including endocytosis, lipid and atherosclerosis, toll-like receptor, TNF, and PI3K-Akt pathway. CONCLUSION: Overall, our study systematically revealed for the first time the differences in plasma exosome contents between non-depressed and depressed rats after TSCI, which will help broaden our understanding of the complex molecular mechanisms involved in brain functional recombination after TSCI.

Hippo cooperates with p53 to maintain foregut homeostasis and suppress the malignant transformation of foregut basal progenitor cells.

Basal progenitor cells serve as a stem cell pool to maintain the homeostasis of the epithelium of the foregut, including the esophagus and the forestomach. Aberrant genetic regulation in these cells can lead to carcinogenesis, such as squamous cell carcinoma (SCC). However, the underlying molecular mechanisms regulating the function of basal progenitor cells remain largely unknown. Here, we use mouse models to reveal that Hippo signaling is required for maintaining the homeostasis of the foregut epithelium and cooperates with p53 to repress the initiation of foregut SCC. Deletion of Mst1/2 in mice leads to epithelial overgrowth in both the esophagus and forestomach. Further molecular studies find that Mst1/2-deficiency promotes epithelial growth by enhancing basal cell proliferation in a Yes-associated protein (Yap)-dependent manner. Moreover, Mst1/2 deficiency accelerates the onset of foregut SCC in a carcinogen-induced foregut SCC mouse model, depending on Yap. Significantly, a combined deletion of Mst1/2 and p53 in basal progenitor cells sufficiently drives the initiation of foregut SCC. Therefore, our studies shed light on the collaborative role of Hippo signaling and p53 in maintaining squamous epithelial homeostasis while suppressing malignant transformation of basal stem cells within the foregut.

CRISPR/Cas9-Mediated Generation of Mutant Lines in Medicago truncatula Indicates a Symbiotic Role of MtLYK10 during Nodule Formation.

CRISPR/Cas9 systems are commonly used for plant genome editing; however, the generation of homozygous mutant lines in Medicago truncatula remains challenging. Here, we present a CRISPR/Cas9-based protocol that allows the efficient generation of M. truncatula mutants. Gene editing was performed for the LysM receptor kinase gene MtLYK10 and two major facilitator superfamily transporter genes. The functionality of CRISPR/Cas9 vectors was tested in Nicotiana benthamiana leaves by editing a co-transformed GUSPlus gene. Transformed M. truncatula leaf explants were regenerated to whole plants at high efficiency (80%). An editing efficiency (frequency of mutations at a given target site) of up to 70% was reached in the regenerated plants. Plants with MtLYK10 knockout mutations were propagated, and three independent homozygous mutant lines were further characterized. No off-target mutations were identified in these lyk10 mutants. Finally, the lyk10 mutants and wild-type plants were compared with respect to the formation of root nodules induced by nitrogen-fixing Sinorhizobium meliloti bacteria. Nodule formation was considerably delayed in the three lyk10 mutant lines. Surprisingly, the size of the rare nodules in mutant plants was higher than in wild-type plants. In conclusion, the symbiotic characterization of lyk10 mutants generated with the developed CRISPR/Cas9 protocol indicated a role of MtLYK10 in nodule formation.

A novel olfactory biosensor based on ZIF-8@SWCNT integrated with nanosome-AuNPs/Prussian blue for sensitive detection of hexanal.

Hexanal is considered as an important volatile compound indicator for the assessment of freshness and maturity of foods. Therefore, sensitive and stable monitoring of hexanal is highly desired. Herein, an efficient receptor immobilization strategy based on ZIF-8@ Single-walled carbon nanotube (SWCNT) and nanosomes-AuNPs/Prussian blue (PB) was proposed for the development of olfactory biosensors. ZIF-8@SWCNT as dual support materials provided a high density of active sites for nanosomes loading. Moreover, the co-electrodeposition of nanosomes-AuNPs and PB on the sensor interface effectively amplified the electrochemical signal and maintained the activity of the receptor. The combination of ZIF-8@SWCNT with AuNPs/PB imparts excellent sensing performance of the biosensor with a wide detection range of 10-16-10-9 M, a low detection limit of 10-16 M for hexanal, and a long storage stability of 15 days. These results indicate that our biosensor can be a powerful tool for versatile applications in food and other related industries.

Impact of the COVID-19 Pandemic on the Professional Attitudes of Medical Students: A Pre-Post-Like Study.

OBJECTIVE: This study assesses the difference in professional attitudes among medical students, both before and after coronavirus disease 2019 (COVID-19), and identifies the determinants closely associated with it, while providing precise and scientific evidence for implementing precision education on such professional attitudes. METHODS: A pre-post-like study was conducted among medical students in 31 provinces in mainland China, from March 23, to April 19, 2021. RESULTS: The proportion of medical students whose professional attitudes were disturbed after the COVID-19 pandemic, was significantly lower than before the COVID-19 pandemic (χ2 = 15.6216; P < 0.0001). Compared with the "undisturbed -undisturbed" group, the "undisturbed-disturbed" group showed that there was a 1.664-fold risk of professional attitudes disturbed as grade increased, 3.269-fold risk when others suggested they choose a medical career rather than their own desire, and 7.557-fold risk for students with COVID-19 in their family, relatives, or friends; while the "disturbed-undisturbed" group showed that students with internship experience for professional attitudes strengthened was 2.933-fold than those without internship experience. CONCLUSIONS: The professional attitudes of medical students have been strengthened during the COVID-19 pandemic. The results provide evidence of the importance of education on professional attitudes among medical students during public health emergencies.

The Influence of Heat Treatment Temperature on Tensile Properties of Metal-Bonded Diamond Composites Fabricated via Selective Laser Melting.

Selective Laser Melting (SLM) is an effective technology for fabricating new types of porous metal-bonded diamond tools with complex geometries. However, due to the high cooling rate and internal stresses during SLM fabrication, defects such as high porosities and interface gaps still need to be resolved before it can be considered for use in other applications. The influence of heat treatment temperature on internal characterization, interface microstructures, and tensile properties of AlSi7Mg-bonded diamond composites fabricated by SLM were investigated in this work. From experimental results, the porosities of HT-200, HT-350, and HT-500 specimens were 12.19%, 11.37%, and 11.14%, respectively, showing a slightly lower percentage than that of the No-HT specimen (13.34%). Here, HT represents "Heat Treatment". For No-HT specimens, an obvious un-bonding area can be seen in the interface between AlSi7Mg and diamond, whereas a relative closer interface can be observed for HT-500 specimens. After heat treatment, the elastic modulus of specimens showed a relative stable value (16.77 ± 2.79~18.23 ± 1.72 GPa), while the value of yield strength decreased from 97.24 ± 4.48 to 44.94 ± 7.06 MPa and the value of elongation increased from 1.98 ± 0.05 to 6.62 ± 0.51%. This difference can be attributed mainly to the disappearance of the solid-solution hardening effect due to the increase of Si content after heat treatment.

TOR-mediated Ypt1 phosphorylation regulates autophagy initiation complex assembly.

The regulation of autophagy initiation is a key step in autophagosome biogenesis. However, our understanding of the molecular mechanisms underlying the stepwise assembly of ATG proteins during this process remains incomplete. The Rab GTPase Ypt1/Rab1 is recognized as an essential autophagy regulator. Here, we identify Atg23 and Atg17 as binding partners of Ypt1, with their direct interaction proving crucial for the stepwise assembly of autophagy initiation complexes. Disruption of Ypt1-Atg23 binding results in significantly reduced Atg9 interactions with Atg11, Atg13, and Atg17, thus preventing the recruitment of Atg9 vesicles to the phagophore assembly site (PAS). Likewise, Ypt1-Atg17 binding contributes to the PAS recruitment of Ypt1 and Atg1. Importantly, we found that Ypt1 is phosphorylated by TOR at the Ser174 residue. Converting this residue to alanine blocks Ypt1 phosphorylation by TOR and enhances autophagy. Conversely, the Ypt1S174D phosphorylation mimic impairs both PAS recruitment and activation of Atg1, thus inhibiting subsequent autophagy. Thus, we propose TOR-mediated Ypt1 as a multifunctional assembly factor that controls autophagy initiation via its regulation of the stepwise assembly of ATG proteins.

RLI2 regulates Arabidopsis female gametophyte and embryo development by facilitating the assembly of the translational machinery.

Eukaryotic protein translation is a complex process that requires the participation of different proteins. Defects in the translational machinery often result in embryonic lethality or severe growth defects. Here, we report that RNase L inhibitor 2/ATP-BINDING CASSETTE E2 (RLI2/ABCE2) regulates translation in Arabidopsis thaliana. Null mutation of rli2 is gametophytic and embryonic lethal, whereas knockdown of RLI2 causes pleiotropic developmental defects. RLI2 interacts with several translation-related factors. Knockdown of RLI2 affects the translational efficiency of a subset of proteins involved in translation regulation and embryo development, indicating that RLI2 has critical roles in these processes. In particular, RLI2 knockdown mutant exhibits decreased expression of genes involved in auxin signaling and female gametophyte and embryo development. Therefore, our results reveal that RLI2 facilitates assembly of the translational machinery and indirectly modulates auxin signaling to regulate plant growth and development.

An extracellular ß-N-acetylhexosaminidase of Medicago truncatula hydrolyzes chitooligosaccharides and is involved in arbuscular mycorrhizal symbiosis but not required for nodulation.

Establishment of symbiosis between plants and arbuscular mycorrhizal (AM) fungi depends on fungal chitooligosaccharides (COs) and lipo-chitooligosaccharides (LCOs). The latter are also produced by nitrogen-fixing rhizobia to induce nodules on leguminous roots. However, host enzymes regulating structure and levels of these signals remain largely unknown. Here, we analyzed the expression of a ß-N-acetylhexosaminidase gene of Medicago truncatula (MtHEXO2) and biochemically characterized the enzyme. Mutant analysis was performed to study the role of MtHEXO2 during symbiosis. We found that expression of MtHEXO2 is associated with AM symbiosis and nodulation. MtHEXO2 expression in the rhizodermis was upregulated in response to applied chitotetraose, chitoheptaose, and LCOs. M. truncatula mutants deficient in symbiotic signaling did not show induction of MtHEXO2. Subcellular localization analysis indicated that MtHEXO2 is an extracellular protein. Biochemical analysis showed that recombinant MtHEXO2 does not cleave LCOs but can degrade COs into N-acetylglucosamine (GlcNAc). Hexo2 mutants exhibited reduced colonization by AM fungi; however, nodulation was not affected in hexo2 mutants. In conclusion, we identified an enzyme, which inactivates COs and promotes the AM symbiosis. We hypothesize that GlcNAc produced by MtHEXO2 may function as a secondary symbiotic signal.

Prevalence of neutropenia in US residents: a population based analysis of NHANES 2011-2018.

AIMS: Neutrophils play a pivotal in immunity and inflammation. We aim to investigate the prevalence of neutropenia in the United States. METHODS: In this cross-sectional study, participants from the National Health and Nutrition Examination Survey (NHANES) (2011-2018) were enrolled. Demographic information, hematologic measurements, smoking status of all participants were collected for all participants. All statistical analyses were performed utilizing the NHANES survey weights. Covariate-adjusted linear regression was used to compare hematologic indices in different population grouped by age, sex, ethnicity, and smoking. We also employed multivariate-logistic regression to estimate the weighted odds ratio with a 95% confidence interval and predict the neutropenia risk among. RESULTS: 32,102 participants from NHANES survey were included, represented 286.6 million multiracial population in the United States. Black participants had lower mean leukocyte count (mean difference (MD): 0.71 × 109/L; P < 0.001) and lower neutrophil count (MD: 0.83 × 109/L; P < 0.001) compared with white participants after adjusting for age and sex. Furthermore, t a notable observation was the significant downward shift in the distribution curves of leukocyte count and neutrophil count among black participants. Smokers had a higher mean leukocyte count (MD: 1.10 × 109 cells/L; P < 0.001) and a higher mean neutrophil count (MD: 0.75 × 109 cells/L; P < 0.001) comparing with nonsmokers. The estimated prevalence of neutropenia was 1.24% (95% CI: 1.11 - 1.37%), which corresponds to approximately 35.5 million individuals in the United States. The prevalence of neutropenia in black participants was significantly higher than other races. Results of logistic regression analysis showed that black individuals, male individuals, and children younger than 5 years had a higher risk of neutropenia. CONCLUSIONS: Neutropenia is more common in the general population than we thought, especially in black individuals and children. More attention should be paid to neutropenia.

The L-shaped correlation between systolic blood pressure and short-term and long-term mortality in patients with cerebral hemorrhage.

BACKGROUND: A large amount of evidence has shown the necessity of lowering blood pressure (BP) in patients with acute cerebral hemorrhage, but whether reducing BP contributes to lower short-term and long-term mortality in these patients remains uncertain. AIMS: We aimed to explore the association between BP, including systolic and diastolic BP, during intensive care unit (ICU) admission and 1-month and 1-year mortality after discharge of patients with cerebral hemorrhage. METHODS: A total of 1085 patients with cerebral hemorrhage were obtained from the Medical Information Mart for Intensive Care III (MIMIC-III) database. Maximum and minimum values of systolic and diastolic BP in these patients during their ICU stay were recorded, and endpoint events were defined as the 1-month mortality and 1-year mortality after the first admission. Multivariable adjusted models were performed for the association of BP with the endpoint events. RESULTS: We observed that patients with hypertension were likely to be older, Asian or Black and had worse health insurance and higher systolic BP than those without hypertension. The logistic regression analysis showed inverse relationships between systolic BP-min (odds ratio (OR) = 0.986, 95% CI 0.983-0.989, P < 0.001) and diastolic BP-min (OR = 0.975, 95% CI 0.968-0.981, P < 0.001) and risks of 1-month, as well as 1-year mortality when controlling for confounders including age, sex, race, insurance, heart failure, myocardial infarct, malignancy, cerebral infarction, diabetes and chronic kidney disease. Furthermore, smooth curve analysis suggested an approximate L-shaped association of systolic BP with the risk of 1-month mortality and 1-year mortality. Reducing systolic BP in the range of 100-150 mmHg has a lower death risk in these patients with cerebral hemorrhage. CONCLUSION: We observed an L-shaped association between systolic BP levels and the risks of 1-month and 1-year mortality in patients with cerebral hemorrhage, which supported that lowering BP when treating an acute hypertensive response could reduce short-term and long-term mortality.

Whole genome sequencing and evolution analyses of Human metapneumovirus.

Human metapneumovirus (HMPV) is a major pathogen of acute respiratory tract infections (ARTIs) in children. Whole genome sequence analyses could help understand the evolution and transmission events of this virus. In this study, we sequenced HMPV whole genomes to improve the identification of molecular epidemiology in Beijing, China. Nasopharyngeal aspirates of hospitalized children aged < 14 years old with ARTIs were screened for HMPV infection using qPCR. Fourteen pairs of overlapping primers were used to amplify whole genome sequences of HMPV from positive samples with high viral loads. The epidemiology of HMPV was analysed and 27 HMPV whole genome sequences were obtained. Sequence identity and the positional entropy analyses showed that most regions of HMPV genome are conserved, whereas the G gene contained many variations. Phylogenetic analysis identified 25 HMPV sequences that belonged to a newly defined subtype A2b1; G gene sequences from 24 of these contained a 111-nucleotide duplication. HMPV is an important respiratory pathogen in paediatric patients. The new subtype A2b1 with a 111-nucleotide duplication has become predominate in Beijing, China.

Ginsenoside Rg1 attenuation of neurogenesis disorder and neuronal apoptosis in the rat hippocampus after spinal cord injury may involve brain-derived neurotrophic factor/extracellular signal-regulated kinase signaling.

OBJECTIVE: We previously demonstrated that spinal cord injury (SCI) induced hippocampus injury and depression in rodents. Ginsenoside Rg1 effectively prevents neurodegenerative disorders. Here, we investigated the effects of ginsenoside Rg1 on the hippocampus after SCI. METHODS: We used a rat compression SCI model. Western blotting and morphologic assays were used to investigate the protective effects of ginsenoside Rg1 in the hippocampus. RESULTS: Brain-derived neurotrophic factor/extracellular signal-regulated kinases (BDNF/ERK) signaling was altered in the hippocampus at 5 weeks after SCI. SCI attenuated neurogenesis and enhanced the expression of cleaved caspase-3 in the hippocampus; however, ginsenoside Rg1 attenuated cleaved caspase-3 expression and improved neurogenesis and BDNF/ERK signaling in the rat hippocampus. The results suggest that SCI affects BDNF/ERK signaling, and ginsenoside Rg1 can attenuate hippocampal damage after SCI. CONCLUSION: We speculate that the protective effects of ginsenoside Rg1 in hippocampal pathophysiology after SCI may involve BDNF/ERK signaling. Ginsenoside Rg1 shows promise as a therapeutic pharmaceutical product when seeking to counter SCI-induced hippocampal damage.

Gender difference in association between low muscle mass and risk of non-alcoholic fatty liver disease among Chinese adults with visceral obesity.

Background and aims: Although the association between low muscle mass and the risk of non-alcoholic fatty liver disease is well-known, it has not been explored in viscerally obese populations by gender. Besides, whether low muscle mass still increases the NAFLD risk in subjects with visceral obesity, independent of obesity, is still unknown. The aim of this study was to explore the gender-specific association between low muscle mass and the risk of non-alcoholic fatty liver disease (NAFLD) in subjects with visceral obesity. Methods: Overall, 1,114 participants aged 19-89 years were recruited in this retrospective study. Liver disease was diagnosed by hepatic ultrasound. Skeletal muscle mass was estimated by bioimpedance analysis and defined by the appendicular skeletal muscle index (ASMI). Gender-specific differences in the ASMI value were compared between NAFLD and control groups. Restricted cubic spline and multivariate logistic regression were performed to analyze the association (stratified by gender and age) between the ASMI and the risk of NAFLD, respectively. Results: Middle-aged females (40-60 years) and males (of any age) with NAFLD had a significantly lower ASMI compared with controls (P-value < 0.05). An inverse linear association was found between the ASMI and risk of NAFLD (all P fornon-linearity > 0.05). Lower quartiles of the ASMI conferred independent risk of NAFLD compared to higher quartiles (all P for trend < 0.001). Low muscle mass conferred a higher risk of NAFLD in middle-aged females (adjusted odds ratio = 2.43, 95% confidence interval: 1.19-4.95) and males [18-39 years: 3.76 (1.79-7.91); 40-60 years: 4.50 (2.16-9.39); and >60 years: 4.10 (1.13-14.84)]. Besides, Low muscle mass and low muscle mass with obesity increase the risk of developing NAFLD, independent of obesity. Conclusion: Among those with visceral obesity, low muscle mass increased the risk of NAFLD in males of any age, and middle-aged females, this may be explained by the postmenopausal decline in estrogen.

The Medicago truncatula hydrolase MtCHIT5b degrades Nod factors of Sinorhizobium meliloti and cooperates with MtNFH1 to regulate the nodule symbiosis.

Nod factors secreted by nitrogen-fixing rhizobia are lipo-chitooligosaccharidic signals required for establishment of the nodule symbiosis with legumes. In Medicago truncatula, the Nod factor hydrolase 1 (MtNFH1) was found to cleave Nod factors of Sinorhizobium meliloti. Here, we report that the class V chitinase MtCHIT5b of M. truncatula expressed in Escherichia coli can release lipodisaccharides from Nod factors. Analysis of M. truncatula mutant plants indicated that MtCHIT5b, together with MtNFH1, degrades S. meliloti Nod factors in the rhizosphere. MtCHIT5b expression was induced by treatment of roots with purified Nod factors or inoculation with rhizobia. MtCHIT5b with a fluorescent tag was detected in the infection pocket of root hairs. Nodulation of a MtCHIT5b knockout mutant was not significantly altered whereas overexpression of MtCHIT5b resulted in fewer nodules. Reduced nodulation was observed when MtCHIT5b and MtNFH1 were simultaneously silenced in RNA interference experiments. Overall, this study shows that nodule formation of M. truncatula is regulated by a second Nod factor cleaving hydrolase in addition to MtNFH1.

Human metapneumovirus in hospitalized children with acute respiratory tract infections in Beijing, China.

BACKGROUND: This study aims to described the epidemiology and genotypic diversity of Human metapneumovirus (HMPV) and the impact of SARS-CoV-2 on the prevalence of HMPV in hospitalized children with Acute respiratory tract infections (ARTIs) in Beijing, China. METHODS: From April 2018 to March 2019 and from September 2020 to August 2021, nasopharyngeal aspirates (NPAs) from hospitalized children with ARTIs in Beijing were collected and subjected to real-time polymerase chain reaction tests for HMPV. Then genotyping, detection of 15 common respiratory viruses and clinical characteristics were analyzed on HMPV positive samples. RESULTS: 7.9% (124/1572) enrolled pediatric patients were identified as having HMPV infection, and the majority of children under the age of 5 (78.2%, 92/124), From April 2018 to March 2019. The detection rate of HMPV in spring and winter is significantly higher than that in summer and autumn. The co-infection rate were 37.1% (46/124), the most common co-infected virus were parainfluenza virus type 3 (HPIV-3). The main diagnosis of HMPV infection was pneumonia (92.7%,115/124), most patient have cough and fever. Of 78 HMPV-positive specimens, A2b (82.1%,64/78) were the main epidemic subtypes. Hospitalized children with HMPV genotype A infection had a higher viral load compared to genotype B. During the COVID-19 outbreak, Among 232 samples, only 4 cases were HMPV-positive. After statistical test, the detection rate of HMPV during the COVID-19 pandemic has decreased significantly compared with that before the epidemic (p = 0.001). CONCLUSIONS: HMPV is an important cause of ARTIs in children under 5 years old. The epidemic peak is generally in winter and spring, and the A2b subtype is the most common. However, under the prevention and control of the COVID-19 pandemic, the HMPV infection of hospitalized children with ARTIs has decreased significantly.

The entry of unclosed autophagosomes into vacuoles and its physiological relevance.

It is widely stated in the literature that closed mature autophagosomes (APs) fuse with lysosomes/vacuoles during macroautophagy/autophagy. Previously, we showed that unclosed APs accumulated as clusters outside vacuoles in Vps21/Rab5 and ESCRT mutants after a short period of nitrogen starvation. However, the fate of such unclosed APs remains unclear. In this study, we used a combination of cellular and biochemical approaches to show that unclosed double-membrane APs entered vacuoles and formed unclosed single-membrane autophagic bodies after prolonged nitrogen starvation or rapamycin treatment. Vacuolar hydrolases, vacuolar transport chaperon (VTC) proteins, Ypt7, and Vam3 were all involved in the entry of unclosed double-membrane APs into vacuoles in Vps21-mutant cells. Overexpression of the vacuolar hydrolases, Pep4 or Prb1, or depletion of most VTC proteins promoted the entry of unclosed APs into vacuoles in Vps21-mutant cells, whereas depletion of Pep4 and/or Prb1 delayed the entry into vacuoles. In contrast to the complete infertility of diploid cells of typical autophagy mutants, diploid cells of Vps21 mutant progressed through meiosis to sporulation, benefiting from the entry of unclosed APs into vacuoles after prolonged nitrogen starvation. Overall, these data represent a new observation that unclosed double-membrane APs can enter vacuoles after prolonged autophagy induction, most likely as a survival strategy.

Vps21 Directs the PI3K-PI(3)P-Atg21-Atg16 Module to Phagophores via Vps8 for Autophagy.

Phosphatidylinositol 3-phosphate (PI(3)P) serves important functions in endocytosis, phagocytosis, and autophagy. PI(3)P is generated by Vps34 of the class III phosphatidylinositol 3-kinase (PI3K) complex. The Vps34-PI3K complex can be divided into Vps34-PI3K class II (containing Vps38, endosomal) and Vps34-PI3K class I (containing Atg14, autophagosomal). Most PI(3)Ps are associated with endosomal membranes. In yeast, the endosomal localization of Vps34 and PI(3)P is tightly regulated by Vps21-module proteins. At yeast phagophore assembly site (PAS) or mammalian omegasomes, PI(3)P binds to WD-repeat protein interacting with phosphoinositide (WIPI) proteins to further recruit two conjugation systems, Atg5-Atg12·Atg16 and Atg8-PE (LC3-II), to initiate autophagy. However, the spatiotemporal regulation of PI(3)P during autophagy remains obscure. Therefore, in this study, we determined the effect of Vps21 on localization and interactions of Vps8, Vps34, Atg21, Atg8, and Atg16 upon autophagy induction. The results showed that Vps21 was required for successive colocalizations and interactions of Vps8-Vps34 and Vps34-Atg21 on endosomes, and Atg21-Atg8/Atg16 on the PAS. In addition to disrupted localization of the PI3K complex II subunits Vps34 and Vps38 on endosomes, the localization of the PI3K complex I subunits Vps34 and Atg14, as well as Atg21, was partly disrupted from the PAS in vps21∆ cells. The impaired PI3K-PI(3)P-Atg21-Atg16 axis in vps21∆ cells might delay autophagy, which is consistent with the delay of early autophagy when Atg21 was absent. This study provides the first insight into the upstream sequential regulation of the PI3K-PI(3)P-Atg21-Atg16 module by Vps21 in autophagy.

Metformin Attenuates Ferroptosis and Promotes Functional Recovery of Spinal Cord Injury.

BACKGROUND: Ferroptosis is involved in traumatic spinal cord injury (SCI), and its inhibition may improve functional recovery after traumatic SCI. This study investigated whether metformin (Met) can have a neuroprotective effect in SCI repair by inhibiting ferroptosis. METHODS: We assessed functional change to determine the long-term effects after intraperitoneal injection of Met in SCI rats with the Basso-Beattie-Bresnahan locomotor rating scale. Malondialdehyde level and relative expression of key proteins, inflammatory cytokines, and nuclear factor E2-related factor 2 signalling molecules were determined in SCI rats and PC12 cells exposed to FeCl3 solution. RESULTS: Met treatment decreased the contents of malondialdehyde, regulated the levels of inflammatory factors, activated the nuclear factor E2-related factor 2 signalling pathway, and improved long-term outcomes by ameliorating SCI-induced locomotor deficits. In vitro studies further confirmed the beneficial and antiferroptotic actions of Met partly through activation of nuclear factor E2-related factor 2 signalling. CONCLUSION: Met can have a neuroprotective effect on SCI repair partly through antiferroptotic effects.