AAV5 delivery of CRISPR/Cas9 mediates genome editing in the lungs of young rhesus monkeys.

Genome editing has the potential to treat genetic diseases in a variety of tissues including the lung. We have previously developed and validated a dual adeno-associated virus (AAV) CRISPR platform that supports effective editing in the airways of mice. To validate this delivery vehicle in a large animal model, we have shown that intratracheal instillation of CRISPR/Cas9 in AAV5 can edit a housekeeping gene or a disease-related gene in the lungs of young rhesus monkeys. We observed up to 8% editing of ACE2 in lung lobes after single-dose administration. Single-nuclear RNA-sequencing revealed that AAV5 transduces multiple cell types in the caudal lung lobes, including alveolar cells, macrophages, fibroblasts, endothelial cells, and B cells. These results demonstrate that AAV5 is efficient in the delivery of CRISPR/Cas9 in the lung lobes of young rhesus monkeys.

A meta-analysis of randomized sham-controlled trials of repetitive transcranial magnetic stimulation for attention-deficit/hyperactivity disorder.

OBJECTIVE: To investigate efficacy of repetitive transcranial magnetic stimulation (rTMS) on attention-deficit/hyperactivity disorder (ADHD). METHODS: Randomized sham-controlled trials (RCTs) were identified from major databases from the inception date of January 1990 to January 2023. Primary outcome was improvement in total symptoms of ADHD. Subgroup analysis focused on rTMS efficacy targeting different brain regions. Secondary outcomes were associations of rTMS with improvements in different symptoms of ADHD. Outcomes were expressed as effect size (ES) based on standardized mean difference (SMD) (continuous data), and odds ratios (ORs) with 95% confidence interval (CI) (categorical data). RESULTS: Meta-analysis of six RCTs involving 169 participants demonstrated no difference in total ADHD symptoms between rTMS-treated participants and sham controls (SMD=-0.24,p=0.17). Subgroup analysis revealed better efficacy of rTMS than sham controls when targeting right prefrontal cortex (rPFC) (SMD=-0.49,p=0.03), but not left prefrontal cortex (lPFC) (SMD= 0.01,p=0.67). rTMS treatment correlated with better improvement in symptoms of inattention (SMD=-0.76,p=0.0002), but not hyperactivity (p=0.86), impulsivity (p=0.41), and depression (p=0.95). The apparently higher risk of dropout in the rTMS group than sham controls was not statistically significant (OR=1.65,p=0.26). CONCLUSIONS: Our study only supported the therapeutic efficacy of rTMS targeting rPFC for the symptoms of ADHD, especially inattention, but not that targeting lPFC. Further large-scale randomized sham-controlled trials are required to verify our findings.

Long-Term Tissue Preservation at Ambient Temperature for Post-Mass Fatality Incident DNA-Based Victim Identification.

In a mass fatality incident (MFI), effective preservation of tissue samples is the cornerstone for downstream DNA-based identification of victims. This is commonly achieved through freezing of tissue samples excised from bodies/fragmented remains which may be buried or stored in refrigerated containers. This may, however, not be possible depending on the nature of the MFI; in particular, during armed conflict/war where extended periods of electrical outages would be expected. The present study compared the effectiveness of long-term tissue preservation at ambient temperatures using two commercial products (non-iodized kitchen salt and a 40% alcoholic beverage) against a chemical preservative (Allprotect™ Tissue Reagent (Qiagen, Germantown, MD, USA)) and freezing at -20 °C. Bovine muscle tissue, used as a proxy for human tissue, was treated with the four preservation methods and sampled at six different time-points over a 24-month period. All four methods were able to preserve the bovine tissue, generally yielding STR-PCR (Short Tandem Repeat-Polymerase Chain Reaction) amplicons > 200 bp in size even at the end of 24 months. Gel electrophoresis, however, indicated that salt was more effective in preserving DNA integrity with high-molecular-weight DNA clearly visible as compared to the low-molecular-weight DNA smears observed in the other methods. This study also proposes a simple process for the rapid and low-cost preservation of tissue samples for long-term storage at ambient temperatures in support of post-incident victim identification efforts.

Therapeutic efficacy of probiotics for symptoms of attention-deficit hyperactivity disorder in children and adolescents: meta-analysis.

BACKGROUND: The efficacy of probiotics as a therapeutic alternative for attention-deficit hyperactivity disorder (ADHD) remain unclear. AIMS: To investigate the effectiveness of probiotics for symptoms of ADHD and identify possible factors affecting their efficacy. METHOD: Randomised placebo-controlled trials were identified through searching major databases from inception to April 2023, using the main keywords 'probiotics' and 'ADHD' without limitation on languages or geographic locations. The outcome of interest included improvement in total symptoms of ADHD, symptoms of inattention and hyperactivity/impulsivity, and drop-out rate. Continuous and categorical data were expressed as effect sizes based on standardised mean differences (SMDs) and odds ratios, respectively, with 95% confidence intervals. RESULTS: Meta-analysis of seven trials involving 379 participants (mean age 10.37 years, range 4-18 years) showed no significant improvement in total symptoms of ADHD (SMD = 0.25; P = 0.12), symptoms of inattention (SMD = 0.14; P = 0.3) or hyperactivity/impulsivity (SMD = 0.08; P = 0.54) between the probiotic and placebo groups. Despite non-significance on subgroup analyses, there was a large difference in effect size between studies using probiotics as an adjunct to methylphenidate and those using probiotics as supplementation (SMD = 0.84 v. 0.07; P = 0.16), and a moderate difference in effect size between studies using multiple strains of probiotics and those using single-strain regimens (SMD = 0.45 v. 0.03; P = 0.19). CONCLUSIONS: Current evidence shows no significant difference in therapeutic efficacy between probiotics and placebos for treatment of ADHD symptoms. However, albeit statistically non-significant, higher therapeutic efficacies associated with multiple-strain probiotics or combining probiotics with methylphenidate may provide direction for further research.

A Fluorescent Reporter Mouse for In Vivo Assessment of Genome Editing with Diverse Cas Nucleases and Prime Editors.

CRISPR-based genome-editing technologies, including nuclease editing, base editing, and prime editing, have recently revolutionized the development of therapeutics targeting disease-causing mutations. To advance the assessment and development of genome editing tools, a robust mouse model is valuable, particularly for evaluating in vivo activity and delivery strategies. In this study, we successfully generated a knock-in mouse line carrying the Traffic Light Reporter design known as TLR-multi-Cas variant 1 (TLR-MCV1). We comprehensively validated the functionality of this mouse model for both in vitro and in vivo nuclease and prime editing. The TLR-MCV1 reporter mouse represents a versatile and powerful tool for expediting the development of editing technologies and their therapeutic applications.

Discrete dynamics of light in an anti-parity-time symmetric photonic lattice in atomic vapors.

We demonstrate the realization of an anti-parity-time (PT)-symmetric photonic lattice in a coherent three-level Λ-type 85Rb atomic system both experimentally and theoretically. Such an instantaneously reconfigurable anti-PT-symmetric photonic lattice is "written" by two one-dimensional coupling fields, which are arranged alternately along the x direction and can modulate the refractive index of the atomic vapor in a spatially periodical manner via controllable atomic coherence. By properly adjusting the relevant atomic parameters, the phase shift between two adjacent lattice channels occurs in the constructed non-Hermitian photonic system. Such a readily reconfigurable anti-PT-symmetric photonic lattice may open the door for demonstrating the discrete characteristics of the optical waves in periodic anti-PT-symmetric photonic systems.

A meta-analysis on the therapeutic efficacy of repetitive transcranial magnetic stimulation for cognitive functions in attention-deficit/hyperactivity disorders.

BACKGROUND: Therapeutic efficacies of repetitive transcranial magnetic stimulation (rTMS) for improving cognitive functions in patients with deficit/hyperactivity disorder (ADHD) remained unclear. The aim of this meta-analysis was to investigate the therapeutic efficacy of rTMS focusing on different cognitive performances. METHODS: Major databases were searched electronically from inception to February 2023 by using keywords mainly "rTMS" and "ADHD" to identify randomized controlled trials (RCTs) that investigated the therapeutic efficacy of rTMS for improving cognitive functions assessed by standardized tasks in patients with ADHD. The overall effect size (ES) was calculated as standardized mean difference (SMD) based on a random effects model. RESULTS: Meta-analysis of five RCTs with 189 participants (mean age of 32.78 and 8.53 years in adult and child/adolescent populations, respectively) demonstrated that rTMS was more effective for improving sustained attention in patients with ADHD compared with the control groups (SMD = 0.54, p = 0.001).Our secondary analysis also showed that rTMS was more effective for improving processing speed than the control groups (SMD = 0.59, p = 0.002) but not for enhancing memory or executive function. CONCLUSIONS: Our results supported the therapeutic efficacy of rTMS for improving sustained attention and processing speed. However, the limitation of available data warrants further studies to verify these findings.

Loss Difference Induced Localization in a Non-Hermitian Honeycomb Photonic Lattice.

Non-Hermitian systems with complex-valued energy spectra provide an extraordinary platform for manipulating unconventional dynamics of light. Here, we demonstrate the localization of light in an instantaneously reconfigurable non-Hermitian honeycomb photonic lattice that is established in a coherently prepared atomic system. One set of the sublattices is optically modulated to introduce the absorptive difference between neighboring lattice sites, where the Dirac points in reciprocal space are extended into dispersionless local flat bands, with two shared eigenstates: low-loss (high-loss) one with fields confined at sublattice B (A). When these local flat bands are broad enough due to larger loss difference, the incident beam with its tangential wave vector being at the K point in reciprocal space is effectively localized at sublattice B with weaker absorption, namely, the commonly seen power exchange between adjacent channels in photonic lattices is effectively prohibited. The current work unlocks a new capability from non-Hermitian two-dimensional photonic lattices and provides an alternative route for engineering tunable local flat bands in photonic structures.

Genome-wide profiling of prime editor off-target sites in vitro and in vivo using PE-tag.

Prime editors have a broad range of potential research and clinical applications. However, methods to delineate their genome-wide editing activities have generally relied on indirect genome-wide editing assessments or the computational prediction of near-cognate sequences. Here we describe a genome-wide approach for the identification of potential prime editor off-target sites, which we call PE-tag. This method relies on the attachment or insertion of an amplification tag at sites of prime editor activity to allow their identification. PE-tag enables genome-wide profiling of off-target sites in vitro using extracted genomic DNA, in mammalian cell lines and in the adult mouse liver. PE-tag components can be delivered in a variety of formats for off-target site detection. Our studies are consistent with the high specificity previously described for prime editor systems, but we find that off-target editing rates are influenced by prime editing guide RNA design. PE-tag represents an accessible, rapid and sensitive approach for the genome-wide identification of prime editor activity and the evaluation of prime editor safety.

Process Optimization of Dual-Liquid Casting and Interfacial Strength-Toughness of the Produced LAS/HCCI Bimetal.

The pouring time interval is the decisive factor of dual-liquid casting for bimetallic productions. Traditionally, the pouring time interval is fully determined by the operator's experience and on-site observation. Thus, the quality of bimetallic castings is unstable. In this work, the pouring time interval of dual-liquid casting for producing low alloy steel/high chromium cast iron (LAS/HCCI) bimetallic hammerheads is optimized via theoretical simulation and experimental verification. The relevancies of interfacial width and bonding strength to pouring time interval are, respectively, established. The results of bonding stress and interfacial microstructure indicate that 40 s is the optimum pouring time interval. The effects of interfacial protective agent on interfacial strength-toughness are also investigated. The addition of the interfacial protective agent yields an increase of 41.5% in interfacial bonding strength and 15.6% in toughness. The optimum dual-liquid casting process is used to produce LAS/HCCI bimetallic hammerheads. Samples cut from these hammerheads show excellent strength-toughness (1188 Mpa for bonding strength and 17 J/cm2 for toughness). The findings could be a reference for dual-liquid casting technology. They are also helpful for understanding the formation theory of the bimetal interface.

Combinatorial design of nanoparticles for pulmonary mRNA delivery and genome editing.

The expanding applications of nonviral genomic medicines in the lung remain restricted by delivery challenges. Here, leveraging a high-throughput platform, we synthesize and screen a combinatorial library of biodegradable ionizable lipids to build inhalable delivery vehicles for messenger RNA and CRISPR-Cas9 gene editors. Lead lipid nanoparticles are amenable for repeated intratracheal dosing and could achieve efficient gene editing in lung epithelium, providing avenues for gene therapy of congenital lung diseases.

MEK1 drives oncogenic signaling and interacts with PARP1 for genomic and metabolic homeostasis in malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is a lethal malignancy etiologically caused by asbestos exposure, for which there are few effective treatment options. Although asbestos carcinogenesis is associated with reactive oxygen species (ROS), the bona fide oncogenic signaling pathways that regulate ROS homeostasis and bypass ROS-evoked apoptosis in MPM are poorly understood. In this study, we demonstrate that the mitogen-activated protein kinase (MAPK) pathway RAS-RAF-MEK-ERK is hyperactive and a molecular driver of MPM, independent of histological subtypes and genetic heterogeneity. Suppression of MAPK signaling by clinically approved MEK inhibitors (MEKi) elicits PARP1 to protect MPM cells from the cytotoxic effects of MAPK pathway blockage. Mechanistically, MEKi induces impairment of homologous recombination (HR) repair proficiency and mitochondrial metabolic activity, which is counterbalanced by pleiotropic PARP1. Consequently, the combination of MEK with PARP inhibitors enhances apoptotic cell death in vitro and in vivo that occurs through coordinated upregulation of cytotoxic ROS in MPM cells, suggesting a mechanism-based, readily translatable strategy to treat this daunting disease. Collectively, our studies uncover a previously unrecognized scenario that hyperactivation of the MAPK pathway is an essential feature of MPM and provide unprecedented evidence that MAPK signaling cooperates with PARP1 to homeostatically maintain ROS levels and escape ROS-mediated apoptosis.

Experimental realization of a reconfigurable Lieb photonic lattice in a coherent atomic medium.

We have experimentally demonstrated the realization of an instantaneously reconfigurable Lieb photonic lattice with a flatband in a three-level Λ-type rubidium atomic configuration. Such a coherently controllable Lieb photonic lattice is optically induced by a coupling field possessing a spatially periodic intensity distribution (generated via a spatial light modulator) under the condition of electromagnetically induced transparency. The incident weak Gaussian probe field can experience discrete diffraction and the observed probe beam at the output surface of the medium exhibits the same Lieb pattern, verifying the formation of the refractive index with a Lieb profile inside the atomic vapor cell. The potential wells and the band structure of the Lieb photonic lattice can be effectively manipulated by easily tuning the frequency of the involved laser beams. The current work can promisingly pave the way for exploring the exotic dynamics as well as tunable photonic devices in Lieb photonic lattices.

Simultaneous Determination of Alternaria Toxins, Ergot Alkaloid Epimers, and Other Major Mycotoxins in Various Food Matrixes by LC-MS/MS.

BACKGROUND: Various food commodities are vulnerable to different types of fungal pathogens and could be contaminated with differential classes of mycotoxins as a result. It is ideal to implement a generic method for the simultaneous determination of multi-mycotoxins in different food matrixes or agricultural products. OBJECTIVE: In this study, a simplified sample preparation procedure and a reliable LC-MS/MS analytical method were developed for the comprehensive measurement of 37 regulated and emerging mycotoxins including five Alternaria toxins (ATs) and six major ergot alkaloids (EAs) and their corresponding epimers. Four different food commodities (baby wheat cereal, peanut, tomato puree, and blended flour) were chosen for method validation to demonstrate the applicability of this analytical method across a wide range of food types. METHODS: Sample extraction was performed using a formic acid-acidified acetonitrile-water (4 + 1, v/v) solution followed by extract dry-down and reconstitution in a water-methanol (1 + 1, v/v) solution for analysis on a biphenyl LC column. Chromatographic analysis was performed using regular acidic LC conditions for baseline separation of ergot alkaloid epimers and completed with a short 11 min cycle time. RESULTS: Accurate quantification was achieved using matrix-matched calibration standards in the range of 0.4 to 400 µg/kg. The recoveries of all mycotoxins (except citrinin) in fortified samples were from 70 to 120%, and the RSD was less than 20%. CONCLUSION: The established workflow was simple and fast for multi-mycotoxin determination in a wide variety of food commodities with LOQs needed to meet the regulatory levels. HIGHLIGHTS: The developed method provided the unique benefit of simultaneous analysis of Alternaria toxins (ATs) and ergot alkaloids (EAs) together with other major regulated mycotoxins.

IMP1/IGF2BP1 in human colorectal cancer extracellular vesicles.

Colorectal cancer (CRC) is a leading cause of cancer-related death. There is an urgent need for new methods of early CRC detection and monitoring to improve patient outcomes. Extracellular vesicles (EVs) are secreted, lipid-bilayer bound, nanoparticles that carry biological cargo throughout the body and in turn exhibit cancer-related biomarker potential. RNA binding proteins (RBPs) are posttranscriptional regulators of gene expression that may provide a link between host cell gene expression and EV phenotypes. Insulin-like growth factor 2 RNA binding protein 1 (IGF2BP1/IMP1) is an RBP that is highly expressed in CRC with higher levels of expression correlating with poor prognosis. IMP1 binds and potently regulates tumor-associated transcripts that may impact CRC EV phenotypes. Our objective was to test whether IMP1 expression levels impact EV secretion and/or cargo. We used RNA sequencing, in vitro CRC cell lines, ex vivo colonoid models, and xenograft mice to test the hypothesis that IMP1 influences EV secretion and/or cargo in human CRC. Our data demonstrate that IMP1 modulates the RNA expression of transcripts associated with extracellular vesicle pathway regulation, but it has no effect on EV secretion levels in vitro or in vivo. Rather, IMP1 appears to affect EV regulation by directly entering EVs in a transformation-dependent manner. These findings suggest that IMP1 has the ability to shape EV cargo in human CRC, which could serve as a diagnostic/prognostic circulating tumor biomarker.NEW & NOTEWORTHY This work demonstrates that the RNA binding protein IGF2BP1/IMP1 alters the transcript profile of colorectal cancer cell (CRC) mRNAs from extracellular vesicle (EV) pathways. IMP1 does not alter EV production or secretion in vitro or in vivo, but rather enters CRC cells where it may further impact EV cargo. Our work shows that IMP1 has the ability to shape EV cargo in human CRC, which could serve as a diagnostic/prognostic circulating tumor biomarker.

The landscape of transcriptional and translational changes over 22 years of bacterial adaptation.

Organisms can adapt to an environment by taking multiple mutational paths. This redundancy at the genetic level, where many mutations have similar phenotypic and fitness effects, can make untangling the molecular mechanisms of complex adaptations difficult. Here, we use the Escherichia coli long-term evolution experiment (LTEE) as a model to address this challenge. To understand how different genomic changes could lead to parallel fitness gains, we characterize the landscape of transcriptional and translational changes across 12 replicate populations evolving in parallel for 50,000 generations. By quantifying absolute changes in mRNA abundances, we show that not only do all evolved lines have more mRNAs but that this increase in mRNA abundance scales with cell size. We also find that despite few shared mutations at the genetic level, clones from replicate populations in the LTEE are remarkably similar in their gene expression patterns at both the transcriptional and translational levels. Furthermore, we show that the majority of the expression changes are due to changes at the transcriptional level with very few translational changes. Finally, we show how mutations in transcriptional regulators lead to consistent and parallel changes in the expression levels of downstream genes. These results deepen our understanding of the molecular mechanisms underlying complex adaptations and provide insights into the repeatability of evolution.

The reason we look like our parents is because we inherit their genes. Genes carry the instructions for our cells to make messenger RNAs (mRNAs), which our cells then translate into proteins. Proteins, in turn, determine many of our features. This is true for all living organisms. Any changes ­ or mutations ­ in an organism's genes can lead to variations in its proteins, which can alter the organism's traits. This is the basis for evolution: mutations can lead to changes that allow an organism to better adapt to a new environment. This increases the organism's chances of survival and reproduction ­ its evolutionary 'fitness' ­ and makes it more likely that the mutation that generated the new trait in the first place will be passed on to the organism's descendants. However, just because two organisms have evolved similar traits to adapt to similar environments, it does not mean that the genetic basis for the adaptation is the same. For example, many animals share similar coloring to warn off predators, but the way that coloring is coded genetically is completely different. In species that are related (which share many of the same genes), this type of evolution is called 'parallel evolution', and it can make it difficult for scientists to understand how an organism evolved and pinpoint exactly what mutations are linked to which features. In 1988, scientists established the 'long-term evolution experiment' to tackle questions about how evolution works. The experiment, which has been running for over 30 years, consisted on tracking the evolution of 12 populations of Escherichia coli bacteria grown in separate flasks containing the same low-nutrient medium. The initial 12 populations were genetically identical, making this an ideal system to study parallel evolution, since all the populations had to evolve to adapt to the same environment, whilst isolated from each other. In previous experiments, scientists had already noted that while the different bacterial populations grew in similar ways, they had mostly different mutations. To better understand parallel evolution, Favate et al. analyzed the synthesis rates of RNA and proteins in the E. coli populations used in the long-term evolution experiment. They found that 22 years after the start of the experiment, all 12 populations produced more RNA, grew faster and were bigger. Additionally, while the different populations had accumulated few shared mutations after 22 years, they all shared similar patterns of RNA levels and protein synthesis rates. Further probing revealed that parallel evolution may be linked to how genes are regulated: mutations in regulators of related groups of genes involved in the same processes inside the cell can amplify the degree of parallel changes in organisms. This means that mutations in these genes may lead to similar traits. These findings provide insight into how parallel evolution arises in the long-term evolution experiment, and provides clues as to how the same traits can evolve several times.

Optically-Induced Symmetry Switching in a Reconfigurable Kagome Photonic Lattice: From Flatband to Type-III Dirac Cones.

We demonstrate the transition of band structure from flatband to type-III Dirac cones in an electromagnetically induced Kagome photonic lattice generated in a three-level Λ-type 85Rb atomic configuration both experimentally and theoretically. Such instantaneously reconfigurable Kagome photonic lattice with flatband is "written" by a strong coupling field possessing a Kagome intensity distribution, which can modulate the refractive index of atomic vapors in a spatially periodical manner under electromagnetically induced transparency. By introducing an additional one-dimensional periodic coupling field to cover any one set of the three inequivalent sublattices of the induced Kagome photonic lattice, the dispersion-less energy band can evolve into type-III Dirac cones with linear dispersion by easily manipulating the intensity of the one-dimensional field. Our results may pave a new route to engineer in situ reconfigurable photonic structures with type-III Dirac cones, which can act as promising platforms to explore the underlying physics and beam dynamics.

Therapeutic effects of antidepressants for global improvement and subdomain symptoms of autism spectrum disorder: a systematic review and meta-analysis.

BACKGROUND: No established pharmacological treatment is available for the core symptoms of autism spectrum disorder (ASD). This study aimed at investigating the efficacy of antidepressants for the core and associated symptoms of ASD. METHODS: We searched PubMed, Embase, ClinicalKey, Cochrane CENTRAL, ScienceDirect, Web of Science and ClinicalTrials.gov using the keywords "ASD" and "antidepressants." We searched from database inception to June 2021 for randomized controlled trials of antidepressant use in patients with ASD. We calculated pooled effect sizes based on a random-effects model. RESULTS: Analysis of 16 studies with 899 participants showed improvements in restricted and repetitive behaviours (effect size = 0.27) and global symptoms (effect size = 1.0) in patients with ASD taking antidepressants versus those taking placebos (p ≤ 0.01). We found no differences between the 2 groups (p ≥ 0.36) in terms of dropout rate (odds ratio [OR] = 1.17) or rate of study discontinuation because of adverse events (OR = 1.05). We also noted improvements in irritability and hyperactivity in the antidepressant group (Hedges g = 0.33 and 0.22, respectively, both p < 0.03). Subgroup analyses showed significant effects of medication type (i.e., clomipramine was better than SSRIs) and age (antidepressants were more effective in adults than in children or adolescents) on both restricted and repetitive behaviours and global improvement (p < 0.05). Meta-regression demonstrated that better therapeutic effects were associated with lower symptom severity and older age. LIMITATIONS: The small effect sizes and variations in treatment response that we found warrant further study. CONCLUSION: Our results supported the effectiveness of antidepressants for global symptoms and symptom subdomains of ASD, with tolerable adverse effects. Low symptom severity and adulthood were associated with better outcomes.

Prevalence and associated factors of suicidal ideation among college students during the COVID-19 pandemic in China: a 3-wave repeated survey.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic, a major public health crisis, harms individuals' mental health. This 3-wave repeated survey aimed to examine the prevalence and correlates of suicidal ideation at different stages of the COVID-19 pandemic in a large sample of college students in China. METHODS: Using a repeated cross-sectional survey design, we conducted 3 online surveys of college students during the COVID-19 pandemic at 22 universities in Guandong, China. The 3 surveys were conducted during the outbreak period (T1: 3 February to 10 February 2020, N = 164,101), remission period (T2: 24 March to 3 April 2020, N = 148,384), and normalized prevention and control period (T3: 1 June to 15 June 2020, N = 159,187). Suicidal ideation was measured by the ninth item of the Patient Health Questionnaire-9. A range of suicide-related factors was assessed, including sociodemographic characteristics, depression, anxiety, insomnia, pre-existing mental health problems, and COVID-19-related factors. RESULTS: The prevalence of suicidal ideation was 8.5%, 11.0% and 12.6% at T1, T2, and T3, respectively. Male sex (aOR: 1.35-1.44, Ps < 0.001), poor self-perceived mental health (aOR: 2.25-2.81, Ps < 0.001), mental diseases (aOR: 1.52-2.09, P < 0.001), prior psychological counseling (aOR: 1.23-1.37, Ps < 0.01), negative perception of the risk of the COVID-19 epidemic (aOR: 1.14-1.36, Ps < 0.001), depressive symptoms (aOR: 2.51-303, Ps < 0.001) and anxiety symptoms (aOR: 1.62-101.11, Ps < 0.001) were associated with an increased risk of suicidal ideation. CONCLUSION: Suicidal ideation appeared to increase during the COVID-19 pandemic remission period among college students in China. Multiple factors, especially mental health problems, are associated with suicidal ideation. Psychosocial interventions should be implemented during and after the COVID-19 pandemic to reduce suicide risk among college students.