Summary
Plants can record external stimuli in mobile mRNAs and systemically deliver them to distal tissues to adjust development. Despite the identification of thousands of mobile mRNAs, the ...functional relevance of mobile mRNAs remains limited.
Many mobile mRNAs are synthesized in the source cells that perceive environmental stimuli, but specifically exert their functions upon transportation to the recipient cells. However, the translation of mobile mRNA‐encoded protein in the source cells could locally activate downstream target genes. How plants avoid ectopic functions of mobile mRNAs in the source cells to achieve tissue specificity remains to be elucidated.
Here, we show that Arabidopsis AGAMOUS‐LIKE 24 (AGL24) is a mobile mRNA whose movement is necessary and sufficient to specify floral organ identity. Although AGL24 mRNA is expressed in vegetative tissues, AGL24 protein exclusively accumulates in the shoot apex. In leaves, AGL24 proteins are degraded to avoid ectopically activating its downstream target genes.
Our results reveal how selective protein degradation in source cells provides a strategy to limit the local effects associated with proteins encoded by mobile mRNAs, which ensures that mobile mRNAs specifically trigger systemic responses only in recipient tissues.
Hebbian and homeostatic plasticity are two major forms of plasticity in the nervous system: Hebbian plasticity provides a synaptic basis for associative learning, whereas homeostatic plasticity ...serves to stabilize network activity. While achieving seemingly very different goals, these two types of plasticity interact functionally through overlapping elements in their respective mechanisms. Here, we review studies conducted in the mammalian central nervous system, summarize known circuit and molecular mechanisms of homeostatic plasticity, and compare these mechanisms with those that mediate Hebbian plasticity. We end with a discussion of ‘local’ homeostatic plasticity and the potential role of local homeostatic plasticity as a form of metaplasticity that modulates a neuron's future capacity for Hebbian plasticity.
This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’.
We conducted a systematic review and meta-analysis to investigate whether the use of statins could be associated with the risk of all-caused dementia, Alzheimer's disease (AD), vascular dementia ...(VaD), and mild cognitive impairment (MCI). Major electronic databases were searched until December 27
, 2017 for studies investigating use of statins and incident cognitive decline in adults. Random-effects meta-analyses calculating relative risks (RRs) were conducted to synthesize effect sizes of individual studies. Twenty-five studies met eligibility criteria. Use of statins was significantly associated with a reduced risk of all-caused dementia (k = 16 studies, adjusted RR (aRR) = 0.849, 95% CI = 0.787-0.916, p = 0.000), AD (k = 14, aRR = 0.719, 95% CI = 0.576-0.899, p = 0.004), and MCI (k = 6, aRR = 0.737, 95% CI = 0.556-0.976, p = 0.033), but no meaningful effects on incident VaD (k = 3, aRR = 1.012, 95% CI = 0.620-1.652, p = 0.961). Subgroup analysis suggested that hydrophilic statins were associated with reduced risk of all-caused dementia (aRR = 0.877; CI = 0.818-0.940; p = 0.000) and possibly lower AD risk (aRR = 0.619; CI = 0.383-1.000; p = 0.050). Lipophilic statins were associated with reduced risk of AD (aRR = 0.639; CI = 0.449-0.908; p = 0.013) but not all-caused dementia (aRR = 0.738; CI = 0.475-1.146; p = 0.176). In conclusion, our meta-analysis suggests that the use of statins may reduce the risk of all-type dementia, AD, and MCI, but not of incident VaD.
Background and aims
Nicotine is a highly addictive substance in tobacco products that dysregulates several neurotransmitters in the brain and impairs executive function. Non‐invasive brain ...stimulation (NIBS) methods such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are promising treatments for nicotine dependence. We investigated the efficacy and acceptability of NIBS in managing smoking cessation through a systematic review and network meta‐analysis (NMA).
Methods
We conducted a systematic review to identify randomized controlled trials (RCTs) that investigated the efficacy of NIBS for smoking cessation. All pairwise meta‐analyses and NMA procedures were conducted using random‐effects and frequentist models. The co‐primary outcomes were (1) the change in number of cigarettes smoked per day (change in frequency of smoking) in patients with nicotine dependence after NIBS and (2) acceptability (the dropout rate). The effect sizes for co‐primary outcomes of change in frequency of smoking and acceptability were assessed according to standardized mean difference (SMD) and odds ratio, respectively.
Results
Twelve RCTs with 710 participants (mean age: 44.2 years, 31.2% female) were included. Compared with the sham control, 10‐Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC) was associated with the largest changes in smoking frequency SMD = −1.22, 95% confidence interval (95% CI) = −1.77 to −0.66. The 2‐mA bifrontal tDCS (SMD = −0.97, 95% CI = −1.32 to −0.62) and 10‐Hz deep rTMS over the bilateral DLPFC with cue provocation (SMD = −0.77, 95% CI = −1.20 to −0.34) were associated with a significantly larger decrease in smoking frequency versus the sham. None of the investigated NIBSs was associated with dropout rates significantly different from those of the sham control groups.
Conclusion
Prefrontal non‐invasive brain stimulation interventions appear to reduce the number of cigarettes smoked with good acceptability.
Floral initiation is orchestrated by systemic floral activators and inhibitors. This remote‐control system may integrate environmental cues to modulate floral initiation. Recently, FLOWERING LOCUS T ...(FT) was found to be a florigen. However, the identity of systemic floral inhibitor or anti‐florigen remains to be elucidated. Here we show that Arabidopsis thaliana CENTRORADIALIS homologue (ATC), an Arabidopsis FT homologue, may act in a non‐cell autonomous manner to inhibit floral initiation. Analysis of the ATC null mutant revealed that ATC is a short‐day‐induced floral inhibitor. Cell type‐specific expression showed that companion cells and apex that express ATC are sufficient to inhibit floral initiation. Histochemical analysis showed that the promoter activity of ATC was mainly found in vasculature but under the detection limit in apex, a finding that suggests that ATC may move from the vasculature to the apex to influence flowering. Consistent with this notion, Arabidopsis seedling grafting experiments demonstrated that ATC moved over a long distance and that floral inhibition by ATC is graft transmissible. ATC probably antagonizes FT activity, because both ATC and FT interact with FD and affect the same downstream meristem identity genes APETALA1, in an opposite manner. Thus, photoperiodic variations may trigger functionally opposite FT homologues to systemically influence floral initiation.
Introduction
Despite its high lifetime prevalence rate and the elevated disability caused by posttraumatic stress disorder (PTSD), treatments exhibit modest efficacy. In consideration of the abnormal ...connectivity between the dorsolateral prefrontal cortex (DLPFC) and amygdala in PTSD, several randomized controlled trials (RCTs) addressing the efficacy of different noninvasive brain stimulation (NIBS) modalities for PTSD management have been undertaken. However, previous RCTs have reported inconsistent results. The current network meta‐analysis (NMA) aimed to compare the efficacy and acceptability of various NIBS protocols in PTSD management.
Methods
We systematically searched ClinicalKey, Cochrane Central Register of Controlled Trials, Embase, ProQuest, PubMed, ScienceDirect, Web of Science, and ClinicalTrials.gov to identify relevant RCTs. The targeted RCTs was those comparing the efficacy of NIBS interventions, such as transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and transcutaneous cervical vagal nerve stimulation, in patients with PTSD. The NMA was conducted using a frequentist model. The primary outcomes were changes in the overall severity of PTSD and acceptability (to be specific, rates of dropouts for any reason).
Results
We identified 14 RCTs that enrolled 686 participants. The NMA demonstrated that among the investigated NIBS types, high‐frequency rTMS over bilateral DLPFCs was associated with the greatest reduction in overall PTSD severity. Further, in comparison with the sham controls, excitatory stimulation over the right DLPFC with/without excitatory stimulation over left DLPFC were associated with significant reductions in PTSD‐related symptoms, including depression and anxiety symptoms, and overall PTSD severity.
Conclusions
This NMA demonstrated that excitatory stimulation over the right DLPFC with or without excitatory stimulation over left DLPFC were associated with significant reductions in PTSD‐related symptoms.
Trial registration: PROSPERO CRD42023391562.
Objectives
To analyze the effect of preoperative body composition on survival in patients with pancreatic cancer following pancreaticoduodenectomy (PD).
Methods
Between October 2005 and August 2018, ...116 patients (68 men, 48 women, mean age 66.2 ± 11.9 years) diagnosed with pancreatic adenocarcinoma following PD were retrospectively enrolled. The preoperative CT on vertebral level L3 was assessed for total abdominal muscle area (TAMA), visceral adipose tissue area (VAT), subcutaneous adipose tissue area (SAT), and mean skeletal muscle attenuation (SMD). The clinical data and pathological findings of tumors were collected. The impact of these factors on disease-free survival (DFS) and overall survival (OS) was evaluated by the Kaplan–Meier method and by univariable and multivariable Cox proportional hazards models.
Results
The 3-year DFS and OS rates were 8% and 25%, respectively. Of 116 patients, 20 (17.2%), 3 (2.6%), and 46 (39.7%) patients were classified as having sarcopenia, sarcopenic obesity, and myosteatosis, respectively. The VAT–TAMA ratio (1.2 ± 0.7 vs 0.9 ± 0.5,
p
= 0.01) and the visceral to subcutaneous adipose tissue area ratio (1.3 ± 0.7 vs 0.9 ± 0.5,
p
= 0.04) were higher in sarcopenic patients than in the nonsarcopenic group. Preoperative sarcopenia and sarcopenic obesity were associated with shorter OS (
p
= 0.012 and
p
= 0.041, respectively), but not shorter DFS. Myosteatosis was neither associated with DFS nor OS. On multivariable analysis, sarcopenia was the only significant prognostic factor for OS (
p
= 0.039).
Conclusions
Preoperative sarcopenia assessed by CT is a poor prognostic factor for OS in pancreatic cancer patients after PD.
Key Points
•
Sarcopenia and sarcopenic obesity can be evaluated by abdominal CT on L3 level.
•
Patients with diabetes mellitus (DM) had lower sex-standardized subcutaneous adipose tissue area index and skeletal muscle density and higher visceral to subcutaneous adipose tissue area ratio than did those without DM.
•
Preoperative sarcopenia, sarcopenic obesity, and new-onset diabetes mellitus may predict poor overall survival in pancreatic cancer patients following pancreaticoduodenectomy.
Mucins are heavily glycosylated proteins that play critical roles in the pathogenesis of tumour malignancies. Pancreatic ductal adenocarcinoma (PDAC) is characterised by the aberrant expression of ...mucins. However, the role of mucin (MUC) 20 in PDAC remains unclear. PDAC is usually surrounded by a dense fibrotic stroma consisting of an extracellular matrix and pancreatic stellate cells (PSCs). The stroma creates a nutrient-deprived, hypoxic, and acidic microenvironment, and promotes the malignant behaviours of PDAC cells. In this study, immunohistochemical staining demonstrated that high MUC20 expression correlated with poor progression-free survival and high local recurrence rate of PDAC patients (n = 61). The expression of MUC20 was induced by serum deprivation, hypoxia, and acidic pH in PDAC cells. MUC20 knockdown with siRNA decreased cell viability, as well as migration and invasion induced by PSCs in HPAC and HPAF-II cells. In intraperitoneal, subcutaneous, and orthotopic injection models, MUC20 knockdown decreased tumour growth in immunodeficient mice. Phospho-RTK array and western blot analysis indicated that MUC20 knockdown decreased HGF-mediated phosphorylation of MET in PDAC cells. Moreover, HGF-induced malignant phenotypes could be suppressed by MUC20 knockdown. Co-immunoprecipitation revealed the physical association of MUC20 and MET. These findings suggest that MUC20 knockdown suppresses the malignant phenotypes of PDAC cells at least partially through the inhibition of the HGF/MET pathway and that MUC20 could act as a potential therapeutic target.
The motile characteristics and mechanisms that drive the dissemination of diffuse large B-cell lymphoma (DLBCL) are elusive. Here, we show that DLBCL initiates dissemination through activating ...STAT3-mediated amoeboid migration. Mechanistically, STAT3 activates RHOH transcription, which competes with the RhoGDP dissociation inhibitor RhoGDIγ to activate RhoA. In addition, activated STAT3 regulates microtubule dynamics and releases ARHGEF2 to activate RhoA. Both the JAK inhibitor ruxolitinib and the microtubule stabilizer Taxol suppress DLBCL cell dissemination in vivo. A clinical DLBCL sample analysis shows that STAT3-driven amoeboid movement is particularly important for the transition from stage I to stage II. This study elucidates the mechanism of DLBCL dissemination and progression and highlights the potential of combating advanced DLBCL with a JAK/STAT inhibitor or microtubule stabilizer to reduce DLBCL motility; these findings may have a great impact on the development of patient-tailored treatments for DLBCL.
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