Rac1 promotes the lipopolysaccharide-induced inflammatory response and contraction-associated proteins (CAPs) expression in mouse uterine smooth muscle cells.

Activation of the maternal immune system leads to a downstream cascade of proinflammatory events that culminate in the activation of spontaneous uterine contractions, which is associated with preterm birth. Ras-related C3 botulinum toxin substrate 1 (Rac1) is a crucial protein related to cell contraction and inflammation. The main purpose of this study was to explore the role and function of Rac1's regulation of inflammation through in- vivo and in-vitro experiments. Rac1 inhibitor was used in animal model of preterm birth and cells isolated from the uterine tissues of pregnant mice on gestational day 16 were transfected with adenovirus to knockdown or overexpress Rac1 and treated with the Calcium-calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93. The expression of Rac1, uterine contraction-associated proteins (CAPs) (COX-2 and Connexin43), and inflammatory cytokines, were assessed by Western blotting and RTPCR. LPS upregulated Rac1, COX-2 and Connexin43 expression in uterine smooth muscle cells (USMCs). The expression of inflammatory cytokines, COX-2, and Connexin43 was significantly decreased in shRac1-transfected cells compared with cells stimulated with LPS only. Rac1 overexpression led to an increase in the expression of inflammatory cytokines, COX-2, and Connexin43. Furthermore, after Rac1 overexpression, KN93 reduced the expression of uterine contraction-associated proteins and inflammatory cytokines. It is thought that the effect of Rac1 on inflammatory cytokine and contraction-associated protein expression in USMCs is mediated by CaMKII. Rac1 can modulate the expression of contraction-associated proteins and inflammatory cytokines through the CaMKII pathway. Rac1 could be an effective therapeutic target for improving the outcome of preterm birth.

Lymphangioleiomyomatosis and pregnancy: a mini-review.

Lymphangioleiomyomatosis(LAM) is a slow progressive, rare cystic lung disease in women of reproductive age, associated with infiltration of the lung by atypical smooth muscle like cells, leading to the cystic destruction of the lung parenchyma. As LAM exclusively affects women of childbearing age, it can arise or exacerbate during pregnancy. Many patients with LAM are discouraged from pregnancy, although there is not much objective evidence effect on fertility. Patients diagnosed with LAM during pregnancy experience worse outcomes, so the safety of pregnancy is a vexing problem. What was worse, treatment strategies are limited on the effects of LAM on pregnancy outcomes. Pregnancy could be considered in LAM patients. Successful delivery in women with LAM depends on the condition of the LAM, which is in turn dependent on obstetricians and respiratory physicians. In this review, we describe the epidemiology, pathogenesis, diagnosis, clinical features and the treatment strategies of LAM during pregnancy.

A Systematic Review and Meta-analysis of the Analgesic Effects of Lidocaine Administered Intravenously or Intraperitoneally Post-Abdominal Surgery.

BACKGROUND: Reducing postoperative pain is still a tremendous challenge for perioperative clinicians. Lidocaine is a local anesthetic that belongs to the amide class and has anti-inflammatory, anti-hyperalgesic, and analgesic effects. Extensive research has been conducted to determine the optimal route for its administration. OBJECTIVE: To compare the efficacy of perioperative intravenous lidocaine with that of intraperitoneal lidocaine on postoperative analgesia in patients undergoing abdominal surgery. STUDY DESIGN: EMBASE, PubMed, and The Cochrane Library were searched for randomized controlled trials published through December 2022 that compared patients receiving perioperative intravenous lidocaine with those receiving intraperitoneal lidocaine. The primary outcome measures included the pain score, as evaluated by the Visual Analog Scale, and opioid analgesia requirements. The secondary outcome measures were hospitalization length, gastrointestinal function recovery, etc. The data were acquired and recorded in electronic spreadsheets that had been designed for this purpose. METHODS: This systematic review's design was based on the Cochrane Handbook for Systematic Reviews of Interventions and was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) method was used to examine the certainty of the evidence. Furthermore, we examined the dependability of the calculated (favorable) treatment effects through considerations of information size and modified significance thresholds (trial sequential analysis). RESULTS: Seven trials including 478 patients were included. Our meta-analysis demonstrates that compared with intravenous lidocaine, patients who received intraperitoneal lidocaine had lower pain scores at 4 hours (mean difference [MD] 1.40; 95% CI, 0.22 to 2.59); 12 hours (MD 0.18; 95% CI, 0.06 to 0.30); and 24 hours (MD -0.12; 95% CI -0.40 to 0.17) postsurgery. However, no obvious difference in opioid consumption (P > 0.05) was found. In addition, the intraperitoneal lidocaine group had a longer postsurgery hospital stay than the intravenous lidocaine group (95%CI, -0.17 to -0.00; I2 = 0%). Intravenous lidocaine was more beneficial for achieving gastrointestinal return than intraperitoneal lidocaine (95% CI, -0.26 to -0.10; I2 = 2%). LIMITATIONS: The sample size of enrolled RCTs was small, which could potentially result in an overestimation or underestimation of the treatment effect in the collected data. There was high heterogeneity among the studies. CONCLUSION: This meta-analysis suggests that post-abdominal surgery intraperitoneal lidocaine administration has a better analgesic effect than intravenous lidocaine, with a lower pain score. However, intravenous lidocaine is more beneficial for gastrointestinal recovery after abdominal surgery.

Identification of subgroups of patients with gastrointestinal cancers based on symptom severity and frequency: A latent profile and latent class analysis.

PURPOSE: Identify subgroups of patients with gastrointestinal cancer with different frequency and severity of symptoms and assess differences in demographics, clinical characteristics, and degree of interference with daily life. METHODS: This was a cross-sectional study. A total of 202 patients with gastrointestinal cancers completed the Chinese version of the MD Anderson Symptom Inventory for Gastrointestinal Cancer Module by convenience sampling. Subgroups of patients were identified using latent profile analysis and latent class analysis. Chi-squared, Mann-Whitney-U, and Kruskal-Wallis tests assessed differences among subgroups. RESULTS: In terms of symptom severity, low (70.3%), Moderate (13.4%), and high (16.3%) classes were identified. Compared with the other two classes, the Moderate group had a higher proportion of patients with a history of tobacco and alcohol, esophageal cancer, and gastric cancer (P < 0.05). In terms of symptom frequency, all -high (57.9%), high physical symptoms (9.9%), and all-low (32.2%) classes were identified. All-high groups had a younger age and a higher proportion of patients with cancer stage IV (P < 0.05). The high group had the most interference with daily life in both perspectives (P < 0.001), and psycho-emotional symptoms were frequent and severe. CONCLUSIONS: The two perspectives of symptom severity and frequency can play a complementary role in identifying high-risk groups. Clinical practitioners should strengthen psychological interventions in young and advanced cancer patients and provide pharmaceutical and non-pharmaceutical interventions for dysphagia symptoms in esophageal and gastric cancer patients with a history of tobacco and alcohol.

Effects of different fractions of inspired oxygen on gas embolization during hysteroscopic surgery: A double-blind, randomized, controlled trial.

OBJECTIVE: Gas embolism is a common complication of hysteroscopic surgery that causes serious concern among gynecologists and anesthesiologists due to the potential risk to patients. The factors influencing gas embolism in hysteroscopic surgery have been extensively studied. However, the effect of the oxygen concentration inhaled by patients on gas embolism during hysteroscopic surgery remains elusive. Therefore, we designed a double-blind, randomized, controlled trial to determine whether different inhaled oxygen concentrations influence the occurrence of gas embolism during hysteroscopic surgery. METHODS: This trial enrolled 162 adult patients undergoing elective hysteroscopic surgery who were randomly divided into three groups with inspired oxygen fractions of 30%, 50%, and 100%. Transthoracic echocardiography (four-chamber view) was used to evaluate whether gas embolism occurred. Before the start of surgery, the four-chamber view was continuously monitored. RESULTS: The number of gas embolisms in the 30%, 50%, and 100% groups was 36 (69.2%), 30 (55.6%), and 24 (44.4%), respectively. The incidence of gas embolism gradually decreased with increasing inhaled oxygen concentration (P = 0.031). CONCLUSION: In hysteroscopic surgery, a higher oxygen concentration inhaled by patients may reduce the incidence of gas embolism, indicating that a higher inhaled oxygen concentration, especially 100%, could be recommended for patients during hysteroscopic surgery. TRIAL REGISTRATION: Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.html?proj=53779, Registration number: ChiCTR2000033202).

Identification of Core Symptom Cluster in Patients With Digestive Cancer: A Network Analysis.

BACKGROUND: A lack of identified core symptom clusters in digestive cancer patients hinders achieving precision symptom intervention. There are few studies on identifying digestive cancer symptom clusters based on network analysis. OBJECTIVES: The aims of this study were to construct the symptom network of digestive cancer patients and identify the core symptom cluster. METHODS: A cross-sectional study was conducted among 202 digestive cancer patients. The Chinese version of the MD Anderson Symptom Inventory for gastrointestinal cancer scale was used to assess the symptoms by convenience sampling. R software was used to construct a symptom network and identify core symptom clusters. Edge weight and centrality difference tests were used to test the accuracy of core symptom cluster identification. RESULTS: The most common symptoms were distress, poor appetite, and sadness. The most serious symptoms were poor appetite, disturbed sleep, and fatigue. The core symptom cluster of the psychoemotional symptom group was distress, sadness, and numbness. The centrality index showed that the top 3 in strength were distress (Rs = 1.11), fatigue (Rs = 1.09), and sadness (Rs = 1.04). The edge weight difference test showed that the psychoemotional symptom group had high stability. CONCLUSIONS: The psychoemotional symptoms of digestive cancer patients should be given priority for intervention. Network analysis must be extended to the symptom research of cancer patients as soon as possible to provide a scientific basis for symptom management. IMPLICATIONS FOR PRACTICE: Nurses must perform comprehensive psychological and emotional assessments, initiate referrals for psychoemotional symptom management and psychological services, and administer pharmacologic and nonpharmacologic interventions to improve appetite loss in digestive cancer patients.

Genetics and genomics knowledge and competency of Chinese nurses based on the theory of diffusion of innovation: A descriptive cross-sectional study.

Background: Nurses are responsible for providing genetics and genomics health care services, including disease risk assessment, medical referrals, and advocating for communities and individuals who probably benefit from genomics and genetics services. Objective: This study aimed to investigate Chinese nurses' understanding and previous training in genomics and genetics. Additionally, we aimed to understand the degree to which Chinese nurses use genomics and genetics knowledge in their daily practice and to assess the learning needs regarding genomics and genetics. Method: This study utilized the design of a descriptive cross-sectional study. From January 18 to March 15, 2022, 406 registered nurses from the Shandong province of China working in clinical institutions and with good English proficiency were recruited as study subjects. Nurses' demographic data and data related to genetic knowledge and competency were collected using the Genetics and Genomics Nursing Practice Survey (GGNPS) questionnaire. Kruskal Wallis and Mann-Whitney-U tests were utilized to investigate the descriptive statistics and non-normally distributed data. Results: There are 406 nurses from Shandong Province, China participated in the study. Among them, BSN degrees accounted for 83.7%. Female nurses accounted for 96.8%, and 40% are clinical nurses. Among such nurses, 65.5% reported that genetics was involved in their nursing courses, and 56.2% planned to study more knowledge associated with genetics. The mean knowledge score was 7.35 (out of 12). Nurses' gender, primary role, genomics education, and experience caring for patients with common diseases influenced nurses' scores on genetic and genomics knowledge. Conclusion: The genomics knowledge and competency of Chinese nurses need to be further improved. Incorporating genomics into the standard nursing curriculum can effectively reduce the knowledge gap. Simultaneously, it is also necessary to improve the attention of senior nurses and nursing managers to genomics nursing and improve the clinical practice environment.

RAC1 is involved in uterine myometrium contraction in the inflammation-associated preterm birth.

In brief: Various etiologies can cause uterine myometrium contraction, which leads to preterm birth. This study demonstrates a new functional relationship between the Ras-related C3 botulinum toxin substrate 1 (RAC1) and uterine myometrium contraction in preterm birth. Abstract: Preterm birth (PTB) is a public health issue. The World Health Organization has recommended the use of tocolytic treatment to inhibit preterm labour and improve pregnancy outcomes. Intrauterine inflammation is associated with preterm birth. RAC1 can modulate inflammation in different experimental settings. In the current study, we explored whether RAC1 can modulate spontaneous uterine myometrium contraction in a mouse model of lipopolysaccharide (LPS)-induced intrauterine inflammation. Subsequently, we recorded uterine myometrium contraction and examined uterine Rac1 expression in a mouse model of preterm birth and a case in pregnant women by Western blotting analysis. We also measured progesterone levels in the blood serum of mice. Murine myometrium was obtained 12 h post LPS treatment. Human myometrium was obtained at the time of caesarean section. We found that in the LPS-treated group of mice, uterine myometrium contraction was enhanced, protein levels and activation of RAC1 were increased and serum progesterone levels were decreased. The protein levels of RAC1 were also increased in preterm birth and in pregnant women. NSC23766, a RAC1 inhibitor, attenuated uterine myometrium contraction and diminished RAC1 activation and COX-2 expression. Furthermore, silencing of RAC1 suppressed cell contraction and COX-2 expression in vitro. In conclusion, our results suggested that RAC1 may play an important role in modulating uterine myometrium contraction. Consequently, intervening with RAC1 represents a novel strategy for the treatment of preterm birth.

Integrative Analysis Identifies a TNFα-Derived Gene Signature for Predicting Prognosis, Tumor Immunity, and Treatment Sensitivity in Gastric Cancer.

Objective: TNF-α is an essential pro-inflammatory cytokine in the tumor microenvironment of gastric cancer (GC), possessing a key biological and clinical impact. Here, we conducted an integrative analysis of the role of TNFα-derived genes in GC prognosis and precision medicine. Methods: We pooled transcriptome and clinical features of GC patients from TCGA and GSE15459 projects. TNFα signaling was quantified through the ssGSEA algorithm, and TNFα-derived genes were screened with WGCNA. Thereafter, a LASSO model was established. The somatic mutation was analyzed across GC specimens. Immune cell infiltrations were inferred through ESTIMATE and ssGSEA algorithms, followed by measuring the immune checkpoint expression. AKR1B1, CPVL, and CTSL expressions were measured in gastric mucosal cells GES-1 and GC cells (HGC-27, MKN-28, and AGS) through RT-qPCR and Western blotting. Results: A TNFα-derived gene signature (containing AKR1B1, CPVL, and CTSL) was developed for GC. A high-risk score indicated more undesirable OS, DFS, DSS, and PFS outcomes. Time-independent ROC curves and multivariate cox regression models confirmed that the signature reliably and independently predicted GC prognosis. Additionally, risk scores displayed significant correlations to more severe histological grades and pathological stages. A low-risk score was characterized by increased somatic mutation, while a high-risk score was characterized by immune and stromal activation, enhanced immune cell infiltrations, and increased expression of immune checkpoint molecules. Experimental results confirmed the significant upregulation of AKR1B1, CPVL, and CTSL in GC cells. Conclusion: Collectively, stratification based on the TNFα-derived gene signature might enable GC patients to predict prognosis, benefit from immunotherapy, and assist in formulating novel therapeutic regimens.

Quantification of Plasmodesmata Permeability in Arabidopsis Leaves by Tracing the Movement of GFP.

Plasmodesmata (PD) play an important role in plant growth and development and defense. The permeability of PD is strictly regulated. Here, we describe an assay for measuring the permeability of PD in Arabidopsis thaliana leaves, which relies on tracing intercellular movement of green fluorescent protein (GFP) upon transient expression of the protein-encoding plasmid delivered by particle bombardment. The method allows to assess GFP movement at single-cell resolution.

Establishment and External Validation of a Hypoxia-Derived Gene Signature for Robustly Predicting Prognosis and Therapeutic Responses in Glioblastoma Multiforme.

OBJECTIVE: Hypoxia presents a salient feature investigated in most solid tumors that holds key roles in cancer progression, including glioblastoma multiforme (GBM). Here, we aimed to construct a hypoxia-derived gene signature for identifying the high-risk GBM patients to guide adjuvant therapy and precision nursing based on signs of hypoxia. METHODS: We retrospectively analyzed the transcriptome profiling and clinicopathological characteristics of GBM from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) cohorts. A series of bioinformatic and machine learning methods were comprehensively applied for establishing a hypoxia-derived gene signature in prediction of overall survival, disease-free survival, disease-specific survival, and progression-free survival. The predictive efficacy of this model was assessed with receiver operator characteristic (ROC) and uni- and multivariate cox regression analysis. The associations of this signature with tumor microenvironment and immunotherapeutic response predictors were evaluated across GBM. RT-qPCR and western blotting were presented for validating the expression of ALDH3B1 and CTSZ in human glioma cell lines (U251, SHG-44, and U87) and normal glial cell line HEB. RESULTS: Among hallmarks of cancer, hypoxia acted as a prominent risk factor of GBM prognosis. A hypoxia-derived gene signature displayed efficient ability in predicting clinical outcomes. High risk score indicated undesirable prognosis, recurrence, and progression of GBM. Moreover, this risk score displayed positive correlations to immunity and stromal activation. Combining immunotherapeutic response predictors, high-risk patients more benefited from immunotherapy. ALDH3B1 and CTSZ expression had prominent upregulation in glioma cells than normal glial cells. CONCLUSION: Collectively, this hypoxia-derived gene signature could become a reliable biomarker for predicting prognosis and therapeutic response and providing theoretical support for hypoxia treatment and precision nursing of GBM patients.

An Update on the Role of the Actin Cytoskeleton in Plasmodesmata: A Focus on Formins.

Cell-to-cell communication in plants is mediated by plasmodesmata (PD) whose permeability is tightly regulated during plant growth and development. The actin cytoskeleton has been implicated in regulating the permeability of PD, but the underlying mechanism remains largely unknown. Recent characterization of PD-localized formin proteins has shed light on the role and mechanism of action of actin in regulating PD-mediated intercellular trafficking. In this mini-review article, we will describe the progress in this area.

Effect of HMGB1 on monocyte immune function in respiratory syncytial virus bronchiolitis.

Expression of high mobility group protein box 1 (HMGB1) in children with respiratory syncytial virus bronchiolitis and its effect on the inflammatory function of monocytes were investigated. A total of 30 cases of respiratory syncytial viral bronchitis and 30 cases of healthy persons from physical examination were collected from January 2017 to September 2019 in the pediatric department of Xuzhou Children's Hospital, Xuzhou Medical University. HMGB1 expression level in plasma was detected by ELISA. All participants in the study were followed up for 18 months. Human recombinant respiratory syncytial virus (RSV)-A2 virus was used to infect human bronchial epithelial cell line 16HBE, and cell culture supernatant was collected to detect HMGB1. Transwell plate was used to co-culture infected or no-infection groups of epithelial cells and monocytes THP-1. Western blot was used to detect the level of Toll-like receptor (TLR)4 and TLR7 in monocytes. HMGB1 expression level in peripheral blood of children with bronchiolitis was significantly increased compared with that in healthy controls (P<0.0001), and was significantly correlated with the severity of the children's condition (P<0.01). The expression level of HMGB1 was significantly correlated with the number of monocytes, lymphocytes and CRP expression level. HMGB1 was also significantly increased in cell culture supernatant compared with no-infection group (P<0.0001). TLR4 expression in monocytes could be activated by the virus infected cell lines. Follow-up results showed that children with bronchiolitis had a higher incidence of asthma within 18 months (P<0.05). The independent risk factors for children to develop asthma were age, number of monocytes and HMGB1 level. HMGB1 is highly expressed in peripheral blood of children with respiratory syncytial virus bronchitis, and RSV epithelial cells can activate TLR4 expression in monocytes, suggesting that HMGB1 plays an important role in monocyte mediated immune inflammation. HMGB1 expression level is related to the development of asthma in children, which is of great significance for understanding the pathogenesis of bronchiolitis and suggesting the prognosis of children.

Organized cannabinoid receptor distribution in neurons revealed by super-resolution fluorescence imaging.

G-protein-coupled receptors (GPCRs) play important roles in cellular functions. However, their intracellular organization is largely unknown. Through investigation of the cannabinoid receptor 1 (CB1), we discovered periodically repeating clusters of CB1 hotspots within the axons of neurons. We observed these CB1 hotspots interact with the membrane-associated periodic skeleton (MPS) forming a complex crucial in the regulation of CB1 signaling. Furthermore, we found that CB1 hotspot periodicity increased upon CB1 agonist application, and these activated CB1 displayed less dynamic movement compared to non-activated CB1. Our results suggest that CB1 forms periodic hotspots organized by the MPS as a mechanism to increase signaling efficacy upon activation.

PSGL-1 inhibits HIV-1 infection by restricting actin dynamics and sequestering HIV envelope proteins.

PSGL-1 has recently been identified as an HIV restriction factor that inhibits HIV DNA synthesis and more potently, virion infectivity. But the underlying mechanisms of these inhibitions are unknown. Here we show that PSGL-1 directly binds to cellular actin filaments (F-actin) to restrict actin dynamics, which leads to inhibition of HIV DNA synthesis. PSGL-1 is incorporated into nascent virions and restricts actin dynamics in the virions, which partially accounts for the inhibition of virion infectivity. More potently, PSGL-1 inhibits incorporation of Env proteins into nascent virions, causing a loss of envelope spikes on the virions as shown by Cryo-electron microscopy and super-resolution imaging. This loss is associated with a profound defect in viral entry. Mechanistically, PSGL-1 binds gp41 and sequesters gp41 at the plasma membrane, explaining the inhibition of Env incorporation in nascent virions. PSGL-1's dual anti-HIV mechanisms represent novel strategies of human cells to defend against HIV infection.

Arabidopsis AIP1-1 regulates the organization of apical actin filaments by promoting their turnover in pollen tubes.

Apical actin filaments are highly dynamic structures that are crucial for rapid pollen tube growth, but the mechanisms regulating their dynamics and spatial organization remain incompletely understood. We here identify that AtAIP1-1 is important for regulating the turnover and organization of apical actin filaments in pollen tubes. AtAIP1-1 is distributed uniformly in the pollen tube and loss of function of AtAIP1-1 affects the organization of the actin cytoskeleton in the pollen tube. Specifically, actin filaments became disorganized within the apical region of aip1-1 pollen tubes. Consistent with the role of apical actin filaments in spatially restricting vesicles in pollen tubes, the apical region occupied by vesicles becomes enlarged in aip1-1 pollen tubes compared to WT. Using ADF1 as a representative actin-depolymerizing factor, we demonstrate that AtAIP1-1 enhances ADF1-mediated actin depolymerization and filament severing in vitro, although AtAIP1-1 alone does not have an obvious effect on actin assembly and disassembly. The dynamics of apical actin filaments are reduced in aip1-1 pollen tubes compared to WT. Our study suggests that AtAIP1-1 works together with ADF to act as a module in regulating the dynamics of apical actin filaments to facilitate the construction of the unique "apical actin structure" in the pollen tube.

A retrospective analysis of infections and antibiotic treatment in patients with Stevens-Johnson syndrome and toxic epidermal necrolysis.

Background: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare drug-related life-threatening acute conditions. Infection is a major cause of morbidity and mortality in these patients. The aim of this study was to analyze the infective characteristics and antimicrobial strategies in patients with SJS and TEN.Methods: A total of 125 patients who were diagnosed with SJS/TEN in West China Hospital from 2010 to 2017 were retrospectively analyzed.Results: There were 75 patients with coinfections (75/125, 60%), of whom 44 had SJS (44/90, 48.9%) and 31 had TEN (31/35, 88.6%). The most common infections were skin infections and pulmonary infections. Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were the most frequently identified pathogenic organisms. The most common antibiotics used in patients with infections were vancomycin, carbapenems, quinolones, macrolides, and lincomycin.Conclusions: Antimicrobial therapy should be administered promptly if there are clinical signs of an infection. Empiric antibiotic selection is based on knowledge of the local microbiota, the different infected sites, the pathogens involved, and the severity of disease.

A SAC Phosphoinositide Phosphatase Controls Rice Development via Hydrolyzing PI4P and PI(4,5)P2.

Phosphoinositides (PIs) as regulatory membrane lipids play essential roles in multiple cellular processes. Although the exact molecular targets of PI-dependent modulation remain largely elusive, the effects of disturbed PI metabolism could be employed to identify regulatory modules associated with particular downstream targets of PIs. Here, we identified the role of GRAIN NUMBER AND PLANT HEIGHT1 (GH1), which encodes a suppressor of actin (SAC) domain-containing phosphatase with unknown function in rice (Oryza sativa). Endoplasmic reticulum-localized GH1 specifically dephosphorylated and hydrolyzed phosphatidylinositol 4-phosphate (PI4P) and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Inactivation of GH1 resulted in massive accumulation of both PI4P and PI(4,5)P2, while excessive GH1 caused their depletion. Notably, superabundant PI4P and PI(4,5)P2 could both disrupt actin cytoskeleton organization and suppress cell elongation. Interestingly, both PI4P and PI(4,5)P2 inhibited actin-related protein2 and -3 (Arp2/3) complex-nucleated actin-branching networks in vitro, whereas PI(4,5)P2 showed more dramatic effects in a dose-dependent manner. Overall, the overaccumulation of PI(4,5)P2 resulting from dysfunction of SAC phosphatase possibly perturbs Arp2/3 complex-mediated actin polymerization, thereby disordering cell development. These findings imply that the Arp2/3 complex might be the potential molecular target of PI(4,5)P2-dependent modulation in eukaryotes, thereby providing insights into the relationship between PI homeostasis and plant growth and development.

Guard Cell Microfilament Analyzer Facilitates the Analysis of the Organization and Dynamics of Actin Filaments in Arabidopsis Guard Cells.

The actin cytoskeleton is involved in regulating stomatal movement, which forms distinct actin arrays within guard cells of stomata with different apertures. How those actin arrays are formed and maintained remains largely unexplored. Elucidation of the dynamic behavior of differently oriented actin filaments in guard cells will enhance our understanding in this regard. Here, we initially developed a program called 'guard cell microfilament analyzer' (GCMA) that enables the selection of individual actin filaments and analysis of their orientations semiautomatically in guard cells. We next traced the dynamics of individual actin filaments and performed careful quantification in open and closed stomata. We found that de novo nucleation of actin filaments occurs at both dorsal and ventral sides of guard cells from open and closed stomata. Interestingly, most of the nucleated actin filaments elongate radially and longitudinally in open and closed stomata, respectively. Strikingly, radial filaments tend to form bundles whereas longitudinal filaments tend to be removed by severing and depolymerization in open stomata. By contrast, longitudinal filaments tend to form bundles that are severed less frequently in closed stomata. These observations provide insights into the formation and maintenance of distinct actin arrays in guard cells in stomata of different apertures.

Effect of carbamylated erythropoietin on neuronal apoptosis in fetal rats during intrauterine hypoxic-ischemic encephalopathy.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) is a common disease that occurs during the perinatal period. The primary cause of neonatal HIE is related to fetal intrauterine anoxia. Carbamylated erythropoietin (CEPO), a derivative of erythropoietin (EPO), does not exert any erythropoietic effect; however, the neuroprotective effects resemble those of EPO. Previous studies have shown the potential benefits of CEPO on the central nervous system. The present study aimed to investigate the role of CEPO in neuronal apoptosis during intrauterine HIE and the underlying mechanisms. RESULTS: To validate our hypothesis, we established an intrauterine HIE model by occluding the bilateral utero-ovarian arteries of pregnant Sprague-Dawley rats. Compared to the I/R group, neuronal apoptosis in the CEPO group was significantly lower at 4, 12, 24, and 48 h (P < 0.05). CEPO significantly inhibited CC3 expression (P < 0.05) during the early-stages after ischemia-reperfusion (0.5, 4, 8, 12 and 24 h), upregulated Bcl-2 expression, and downregulated Bax expression at 4, 8, 12, and 24 h (P < 0.05). CONCLUSIONS: Carbamylated erythropoietin pretreatment inhibited the expression of proapoptotic protein CC3 in brain and regulated the Bcl-2/Bax ratio, resulting in reduced neuronal apoptosis and thus resulting in a protective effect on intrauterine HIE.