A genome-wide screen links peroxisome regulation with Wnt signaling through RNF146 and TNKS/2.

Peroxisomes are membrane-bound organelles harboring metabolic enzymes. In humans, peroxisomes are required for normal development, yet the genes regulating peroxisome function remain unclear. We performed a genome-wide CRISPRi screen to identify novel factors involved in peroxisomal homeostasis. We found that inhibition of RNF146, an E3 ligase activated by poly(ADP-ribose), reduced the import of proteins into peroxisomes. RNF146-mediated loss of peroxisome import depended on the stabilization and activity of the poly(ADP-ribose) polymerases TNKS and TNKS2, which bind the peroxisomal membrane protein PEX14. We propose that RNF146 and TNKS/2 regulate peroxisome import efficiency by PARsylation of proteins at the peroxisome membrane. Interestingly, we found that the loss of peroxisomes increased TNKS/2 and RNF146-dependent degradation of non-peroxisomal substrates, including the ß-catenin destruction complex component AXIN1, which was sufficient to alter the amplitude of ß-catenin transcription. Together, these observations not only suggest previously undescribed roles for RNF146 in peroxisomal regulation but also a novel role in bridging peroxisome function with Wnt/ß-catenin signaling during development.

Engineering water exchange is a safe and effective method for magnetic resonance imaging in diverse cell types.

Aquaporin-1 (Aqp1), a water channel, has garnered significant interest for cell-based medicine and in vivo synthetic biology due to its ability to be genetically encoded to produce magnetic resonance signals by increasing the rate of water diffusion in cells. However, concerns regarding the effects of Aqp1 overexpression and increased membrane diffusivity on cell physiology have limited its widespread use as a deep-tissue reporter. In this study, we present evidence that Aqp1 generates strong diffusion-based magnetic resonance signals without adversely affecting cell viability or morphology in diverse cell lines derived from mice and humans. Our findings indicate that Aqp1 overexpression does not induce ER stress, which is frequently associated with heterologous expression of membrane proteins. Furthermore, we observed that Aqp1 expression had no detrimental effects on native biological activities, such as phagocytosis, immune response, insulin secretion, and tumor cell migration in the analyzed cell lines. These findings should serve to alleviate any lingering safety concerns regarding the utilization of Aqp1 as a genetic reporter and should foster its broader application as a noninvasive reporter for in vivo studies.

Effectiveness of the Minder Mobile Mental Health and Substance Use Intervention for University Students: Randomized Controlled Trial.

BACKGROUND: University attendance represents a transition period for students that often coincides with the emergence of mental health and substance use challenges. Digital interventions have been identified as a promising means of supporting students due to their scalability, adaptability, and acceptability. Minder is a mental health and substance use mobile app that was codeveloped with university students. OBJECTIVE: This study aims to examine the effectiveness of the Minder mobile app in improving mental health and substance use outcomes in a general population of university students. METHODS: A 2-arm, parallel-assignment, single-blinded, 30-day randomized controlled trial was used to evaluate Minder using intention-to-treat analysis. In total, 1489 participants were recruited and randomly assigned to the intervention (n=743, 49.9%) or waitlist control (n=746, 50.1%) condition. The Minder app delivers evidence-based content through an automated chatbot and connects participants with services and university social groups. Participants are also assigned a trained peer coach to support them. The primary outcomes were measured through in-app self-assessments and included changes in general anxiety symptomology, depressive symptomology, and alcohol consumption risk measured using the 7-item General Anxiety Disorder scale, 9-item Patient Health Questionnaire, and US Alcohol Use Disorders Identification Test-Consumption Scale, respectively, from baseline to 30-day follow-up. Secondary outcomes included measures related to changes in the frequency of substance use (cannabis, alcohol, opioids, and nonmedical stimulants) and mental well-being. Generalized linear mixed-effects models were used to examine each outcome. RESULTS: In total, 79.3% (589/743) of participants in the intervention group and 83% (619/746) of participants in the control group completed the follow-up survey. The intervention group had significantly greater average reductions in anxiety symptoms measured using the 7-item General Anxiety Disorder scale (adjusted group mean difference=-0.85, 95% CI -1.27 to -0.42; P<.001; Cohen d=-0.17) and depressive symptoms measured using the 9-item Patient Health Questionnaire (adjusted group mean difference=-0.63, 95% CI -1.08 to -0.17; P=.007; Cohen d=-0.11). A reduction in the US Alcohol Use Disorders Identification Test-Consumption Scale score among intervention participants was also observed, but it was not significant (P=.23). Statistically significant differences in favor of the intervention group were found for mental well-being and reductions in the frequency of cannabis use and typical number of drinks consumed. A total of 77.1% (573/743) of participants in the intervention group accessed at least 1 app component during the study period. CONCLUSIONS: In a general population sample of university students, the Minder app was effective in reducing symptoms of anxiety and depression, with provisional support for increasing mental well-being and reducing the frequency of cannabis and alcohol use. These findings highlight the potential ability of e-tools focused on prevention and early intervention to be integrated into existing university systems to support students' needs. TRIAL REGISTRATION: ClinicalTrials.gov NCT05606601; https://clinicaltrials.gov/ct2/show/NCT05606601. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/49364.

A genome-wide screen links peroxisome regulation with Wnt signaling through RNF146 and tankyrase.

Peroxisomes are membrane-bound organelles harboring metabolic enzymes. In humans, peroxisomes are required for normal development, yet the genes regulating peroxisome function remain unclear. We performed a genome-wide CRISPRi screen to identify novel factors involved in peroxisomal homeostasis. We found that inhibition of RNF146, an E3 ligase activated by poly(ADP-ribose), reduced the import of proteins into peroxisomes. RNF146-mediated loss of peroxisome import depended on the stabilization and activity of the poly(ADP-ribose) polymerase tankyrase, which binds the peroxisomal membrane protein PEX14. We propose that RNF146 and tankyrase regulate peroxisome import efficiency by PARsylation of proteins at the peroxisome membrane. Interestingly, we found that the loss of peroxisomes increased tankyrase and RNF146-dependent degradation of non-peroxisomal substrates, including the beta-catenin destruction complex component AXIN1, which was sufficient to alter the amplitude of beta-catenin transcription. Together, these observations not only suggest previously undescribed roles for RNF146 in peroxisomal regulation, but also a novel role in bridging peroxisome function with Wnt/beta-catenin signaling during development.

The N1 domain of the peroxisomal AAA-ATPase Pex6 is required for Pex15 binding and proper assembly with Pex1.

The heterohexameric ATPases associated with diverse cellular activities (AAA)-ATPase Pex1/Pex6 is essential for the formation and maintenance of peroxisomes. Pex1/Pex6, similar to other AAA-ATPases, uses the energy from ATP hydrolysis to mechanically thread substrate proteins through its central pore, thereby unfolding them. In related AAA-ATPase motors, substrates are recruited through binding to the motor's N-terminal domains or N terminally bound cofactors. Here, we use structural and biochemical techniques to characterize the function of the N1 domain in Pex6 from budding yeast, Saccharomyces cerevisiae. We found that although Pex1/ΔN1-Pex6 is an active ATPase in vitro, it does not support Pex1/Pex6 function at the peroxisome in vivo. An X-ray crystal structure of the isolated Pex6 N1 domain shows that the Pex6 N1 domain shares the same fold as the N-terminal domains of PEX1, CDC48, and NSF, despite poor sequence conservation. Integrating this structure with a cryo-EM reconstruction of Pex1/Pex6, AlphaFold2 predictions, and biochemical assays shows that Pex6 N1 mediates binding to both the peroxisomal membrane tether Pex15 and an extended loop from the D2 ATPase domain of Pex1 that influences Pex1/Pex6 heterohexamer stability. Given the direct interactions with both Pex15 and the D2 ATPase domains, the Pex6 N1 domain is poised to coordinate binding of cofactors and substrates with Pex1/Pex6 ATPase activity.

Harvest graft substitute for soft tissue volume augmentation around existing implants: A randomized, controlled and blinded multicenter trial.

BACKGROUND: Using a single-blind, randomized, controlled, multicenter, practice-based clinical trial, a volume-stable collagen matrix (VCMX) was compared with connective tissue graft (CTG) for soft tissue augmentation around existing dental implants. METHODS: Sixty patients (31 VCMX and 31 CTG) were included. The primary outcome was a soft tissue thickness change 3 mm below the gingival margin (GM). Secondary outcomes included clinical measures, such as keratinized tissue widths (KTw), probing pocket depths, and pink esthetic scores, and patient-reported outcomes (PRO). RESULTS: There were no significant differences between test and control patient demographics or clinical measures throughout the 1-year study. VCMX "grafts" were by design larger than CTG, and surgery time was less (27% less, p = 0.0005). Three millimeters below the GM (primary endpoint), tissue thickness increase was noninferior for VCMX compared with CTG (0.93 ± 0.80 mm vs. 1.10 ± 0.51 mm, respectively), inferior (by 0.25 mm) at 1 mm, and noninferior at 5 mm. Postoperative pain was significantly less for VCMX patients (p < 0.0001), but all other PRO measures, including esthetics and satisfaction, improved similarly for both therapies. CONCLUSIONS: Given the inclusion criteria for this study, namely soft tissue augmentation around existing implants with some evidence of KTw and minimal recession, VCMX provided soft tissue thickness and volume increases similar (noninferior) to CTG. Clinical measures and PRO were similar between therapies-site sensitivity and esthetics improved similarly for both therapies-but surgery time and pain following surgery were significantly less for VCMX.

Patterns of anxiety, depression, and substance use risk behaviors among university students in Canada.

Objective: To identify subgroups of students with distinct profiles of mental health symptoms (MH) and substance use risk (SU) and the extent to which MH history and socio-demographics predict subgroup membership. Participants: University students (N = 10,935: 63% female). Methods: Repeated cross-sectional survey administered weekly to stratified random samples. Latent class analysis (LCA) was used to identify subgroups and multinomial regression was used to examine associations with variables of interest. Results: LCA identified an optimal 4-latent class solution: High MH-Low SU (47%), Low MH-Low SU (22%), High MH-High SU (19%), and Low MH-High SU (12%). MH history, gender, and ethnicity were associated with membership in the classes with high risk of MH, SU, or both. Conclusion: A substantial proportion of students presented with MH, SU, or both. Gender, ethnicity and MH history is associated with specific patterns of MH and SU, offering potentially useful information to tailor early interventions.

Engineering water exchange is a safe and effective method for magnetic resonance imaging in diverse cell types.

Aquaporin-1 (Aqp1), a water channel, has garnered significant interest for cell-based medicine and in vivo synthetic biology due to its ability to be genetically encoded to produce magnetic resonance signals by increasing the rate of water diffusion in cells. However, concerns regarding the effects of Aqp1 overexpression and increased membrane diffusivity on cell physiology have limited its widespread use as a deep-tissue reporter. In this study, we present evidence that Aqp1 generates strong diffusion-based magnetic resonance signals without adversely affecting cell viability or morphology in diverse cell lines derived from mice and humans. Our findings indicate that Aqp1 overexpression does not induce ER stress, which is frequently associated with heterologous expression of membrane proteins. Furthermore, we observed that Aqp1 expression had no detrimental effects on native biological activities, such as phagocytosis, immune response, insulin secretion, and tumor cell migration in the analyzed cell lines. These findings should serve to alleviate any lingering safety concerns regarding the utilization of Aqp1 as a genetic reporter and should foster its broader application as a noninvasive reporter for in vivo studies.

A comparison of Er,Cr:YSGG laser to minimally invasive surgical technique in the treatment of intrabony defects: Twelve-month results of a multicenter, randomized, controlled study.

BACKGROUND: The purpose of this publication is to report on the 12-month clinical and radiographic results comparing the surgical use of the Er,Cr:YSGG laser (ERL) and minimally invasive surgical technique (MIST) for the treatment of intrabony defects in subjects with generalized periodontitis stage III, grade B. METHODS: Fifty-three adult subjects (29 females and 24 males; 19-73 years) with 79 intrabony defects were randomized following scaling and root planing (SRP) to receive ERL monotherapy (n = 27) or MIST (n = 26). Fifty subjects completed the study. Recession (REC), probing depth (PD), clinical attachment level (CAL), treatment time, and standardized radiographs were assessed and compared for each treatment group. Clinical measurements were recorded at baseline, 4-6 weeks following SRP, and 6 and 12 months following surgical therapy. Radiographic results were compared to baseline at 6 and 12 months following surgical therapy. RESULTS: The following primary and secondary outcome variables were non-inferior with the following margins: CAL with a non-inferiority margin of 0.7 mm (p = 0.05), PD with a non-inferiority margin of 0.7 mm (p = 0.05), and REC with a non-inferiority margin of 0.4 mm (p = 0.05). Standardized radiographs suggest similar bone fill of 1.14 ± 1.73 mm for MIST and 1.12 ± 1.52 mm for ERL. CONCLUSIONS: This is the first multicenter, randomized, masked, and controlled study demonstrating the ERL is not inferior to MIST at 12 months in terms of clinical outcomes and similar to MIST in terms of radiographic bone fill for the surgical treatment of intrabony defects.

Parent psychological distress and parent-child relationships two years into the COVID-19 pandemic: Results from a Canadian cross-sectional study.

BACKGROUND: Mental health impacts of the COVID-19 pandemic have not been felt equally within populations. Parents with children living at home were early on identified as a population at heightened mental health risk, with concerns about the potential long-term impacts of the pandemic on parents' mental health, family functioning, and children's well-being. This study investigates impacts of the pandemic on parents' psychological distress, contextual sources of distress, and associations with family functioning nearly two years into the pandemic. METHODS AND FINDINGS: Data were drawn from a national cross-sectional survey of adults living in Canada in November and December 2021 that was representative by age, gender, household income, and region. Parents with children < 18 years old living at home (N = 553) reported their experiences of psychological distress, pandemic-related stressors, coping mechanisms, and family functioning (changes in parent-child interactions, children's anxiety). Chi-square tests, logistic regression, and linear regression analyses examined sociodemographic inequities in parents' levels of psychological distress, sources and mitigating mechanisms of distress, and associations between psychological distress and family functioning. Nearly two years into the pandemic, parents with children at home reported nearly double pre-pandemic population estimates of moderate to severe psychological distress. Psychological distress was more frequently reported among parents with pre-existing mental health conditions, disabilities, and financial stressors. Parents with greater psychological distress reported increases in negative parent-child interactions due to the pandemic and higher anxiety among their children. CONCLUSIONS: This study identifies sustained negative impacts of the pandemic on parents' mental health and family functioning in Canada nearly two years into the pandemic, despite high vaccine uptake and declining infection rates. Disparities in financial stress, social support structures, and pre-existing mental health were identified as underlying sources of psychological distress. These results highlight that meaningful responses to promote mental health among parents and families must address social and structural inequities.

The Pex6 N1 domain is required for Pex15 binding and proper assembly with Pex1.

The heterohexameric AAA-ATPase Pex1/Pex6 is essential for the formation and maintenance of peroxisomes. Pex1/Pex6, similar to other AAA-ATPases, uses the energy from ATP hydrolysis to mechanically thread substrate proteins through its central pore, thereby unfolding them. In related AAA-ATPase motors, substrates are recruited through binding to the motor's N-terminal domains or N-terminally bound co-factors. Here we use structural and biochemical techniques to characterize the function of the N1 domain in Pex6 from budding yeast, S. cerevisiae. We found that although Pex1/ΔN1-Pex6 is an active ATPase in vitro, it does not support Pex1/Pex6 function at the peroxisome in vivo. An X-ray crystal structure of the isolated Pex6 N1 domain shows that the Pex6 N1 domain shares the same fold as the N terminal domains of PEX1, CDC48, or NSF, despite poor sequence conservation. Integrating this structure with a cryo-EM reconstruction of Pex1/Pex6, AlphaFold2 predictions, and biochemical assays shows that Pex6 N1 mediates binding to both the peroxisomal membrane tether Pex15 and an extended loop from the D2 ATPase domain of Pex1 that influences Pex1/Pex6 heterohexamer stability. Given the direct interactions with both Pex15 and the D2 ATPase domains, the Pex6 N1 domain is poised to coordinate binding of co-factors and substrates with Pex1/Pex6 ATPase activity.

Evaluating the Effectiveness of a Codeveloped e-Mental Health Intervention for University Students: Protocol for a Randomized Controlled Trial.

BACKGROUND: University life typically occurs during a period of life transition, where the incidence of mental health and substance use problems and disorders peaks. However, relatively few students obtain effective treatment and support. e-Interventions have proven effective in improving the psychological outcomes of university students and have the potential to provide scalable services that can easily integrate into existing models of care. Minder is a mobile app codeveloped with university students that offers users a collection of evidence-based interventions tailored to help university students maintain their mental health and well-being and manage their substance use. OBJECTIVE: This paper describes the protocol for a randomized controlled trial (RCT) that aims to assess the effectiveness of the Minder app in improving the mental health and substance use outcomes of university students. METHODS: This study is a 2-arm, parallel assignment, single-blinded, 30-day RCT with 1 intervention group and 1 waitlist control group. Overall, 1496 (748 per trial arm) university students from the University of British Columbia Vancouver Campus (N=54,000) who are aged ≥17 years, have a smartphone with Wi-Fi or cellular data, and speak English will be recruited via a variety of web-based and offline strategies. Participants will be randomized into the intervention or control group after completing a baseline survey. Those randomized into the intervention group will gain immediate access to the Minder app and will be assessed at 2 weeks and 30 days. Those randomized into the control group will be given access to the app content after their follow-up assessment at 30 days. The primary outcomes are measured from baseline to follow-up at 30 days and include changes in general anxiety symptomology, depressive symptomology, and alcohol consumption risk measured by the General Anxiety Disorder 7-Item scale, Patient Health Questionnaire 9-Item scale, and US Alcohol Use Disorders Identification Test-Consumption Scale, respectively. Secondary outcomes include measures related to changes in the frequency of substance use, mental well-being, self-efficacy in managing mental health and substance use, readiness to change, and self-reported use of mental health services and supports (including referral) from baseline to follow-up at 30 days. RESULTS: Trial recruitment and data collection began in September 2022, and the completion of data collection for the trial is anticipated by June 2023. As of May 10, 2023, a total of 1425 participants have been enrolled. CONCLUSIONS: The RCT described in this protocol paper will assess whether the Minder app is effective in improving the mental health and substance use outcomes of a general population of Canadian university students. Additional secondary outcome research aims to explore additional outcomes of interest for further research and better understand how to support students' general mental well-being. TRIAL REGISTRATION: ClinicalTrials.gov NCT05606601; https://clinicaltrials.gov/ct2/show/NCT05606601. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/49364.

Mental distress and virtual mental health resource use amid the COVID-19 pandemic: Findings from a cross-sectional study in Canada.

Objective: This paper characterizes levels of mental distress among adults living in Canada amid the COVID-19 pandemic and examines the extent of virtual mental health resource use, including reasons for non-use, among adults with moderate to severe distress. Methods: Data are drawn from a cross-sectional monitoring survey (29 November to 7 December 2021) on the mental health of adults (N = 3030) in Canada during the pandemic. Levels of mental distress were assessed using the Kessler Psychological Distress Scale. Descriptive statistics were used to examine virtual mental health resource use among participants with moderate to severe distress, including self-reported reasons for non-use. Results: Levels of mental distress were classified as none to low (48.8% of participants), moderate (36.6%), and severe (14.6%). Virtual mental health resource use was endorsed by 14.2% of participants with moderate distress and 32% of those with severe distress. Participants with moderate to severe distress reported a range of reasons for not using virtual mental health resources, including not feeling as though they needed help (37.4%), not thinking the supports would be helpful (26.2%), and preferring in-person supports (23.4%), among other reasons. Conclusions: This study identified a high burden of mental distress among adults in Canada during the COVID-19 pandemic alongside an apparent mismatch between actual and perceived need for support, including through virtual mental health resources. Findings on virtual mental health resource use, and reasons for non-use, offer directions for mental health promotion and health communication related to mental health literacy and the awareness and appropriateness of virtual mental health resources.

A Survey Study to Examine Willingness to Travel for Transplantation and Consider Commercial Transplantation Among a Multiethnic Cohort of Canadians.

Introduction: Travel for transplantation is the movement of organs, donors, recipients, or transplant professionals across jurisdictional borders for transplantation purposes and is considered transplant tourism if transplant commercialism is involved. Little is known about the willingness of patients at risk for transplant tourism to engage in this practice. Methods: A cross-sectional survey of patients with end-stage renal disease was conducted in Canada to determine interest in travel for transplantation and transplant tourism, characterize patients according to their willingness to consider transplant tourism, and identify factors to deter willingness to consider transplant tourism. Surveys were conducted face-to-face and in multiple languages. Results: Among the 708 patients surveyed, 418 (59%) reported a willingness to travel outside of Canada for transplantation, with 24% reporting a strong willingness. One hundred sixty-one (23%) reported a willingness to travel and purchase a kidney overseas. On multivariate analysis, male sex, younger age, and Pacific Islander ethnicity were associated with higher odds of willingness to travel for transplant, whereas male sex, annual income greater than $100,000, and Asian and Middle Eastern ethnicity were associated with higher odds of willing to travel to purchase a kidney. Willingness reduced when respondents were informed of medical risks and legal implications related to travel for transplantation. Financial and ethical considerations were less effective at reducing willingness to travel for transplantation. Conclusion: There was a high level of interest in travel for transplantation and transplant tourism. Legal consequences and education on medical risks of transplant tourism may be effective deterrent strategies.

Advancing socioecological mental health promotion intervention: A mixed methods exploration of Phase 1 Agenda Gap findings.

Introduction: Protecting and promoting the mental health of youth under 30 years of age is a priority, globally. Yet investment in mental health promotion, which seeks to strengthen the determinants of positive mental health and wellbeing, remains limited relative to prevention, treatment, and recovery. The aim of this paper is to contribute empirical evidence to guide innovation in youth mental health promotion, detailing the early outcomes of Agenda Gap, an intervention centering youth-led policy advocacy to influence positive mental health for individuals, families, communities and society. Methods: Leveraging a convergent mixed methods design, this study draws on data from n = 18 youth (ages 15 to 17) in British Columbia, Canada, who contributed to pre- and post-intervention surveys and post-intervention qualitative interviews following their participation in Agenda Gap from 2020-2021. These data are supplemented by qualitative interviews with n = 4 policy and other adult allies. Quantitative and qualitative data were analyzed in parallel, using descriptive statistics and reflexive thematic analysis, and then merged for interpretation. Results: Quantitative findings suggest Agenda Gap contributes to improvements in mental health promotion literacy as well as several core positive mental health constructs, such as peer and adult attachment and critical consciousness. However, these findings also point to the need for further scale development, as many of the available measures lack sensitivity to change and are unable to distinguish between higher and lower levels of the underlying construct. Qualitative findings provided nuanced insights into the shifts that resulted from Agenda Gap at the individual, family, and community level, including reconceptualization of mental health, expanded social awareness and agency, and increased capacity for influencing systems change to promote positive mental health and wellbeing. Discussion: Together, these findings illustrate the promise and utility of mental health promotion for generating positive mental health impacts across socioecological domains. Using Agenda Gap as an exemplar, this study underscores that mental health promotion programming can contribute to gains in positive mental health for individual intervention participants whilst also enhancing collective capacity to advance mental health and equity, particularly through policy advocacy and responsive action on the social and structural determinants of mental health.

Interstrand crosslinking of homologous repair template DNA enhances gene editing in human cells.

We describe a strategy to boost the efficiency of gene editing via homology-directed repair (HDR) by covalently modifying the template DNA with interstrand crosslinks. Crosslinked templates (xHDRTs) increase Cas9-mediated editing efficiencies by up to fivefold in K562, HEK293T, U2OS, iPS and primary T cells. Increased editing from xHDRTs is driven by events on the template molecule and requires ataxia telangiectasia and Rad3-related (ATR) kinase and components of the Fanconi anemia pathway.

New advances in CRISPR/Cas-mediated precise gene-editing techniques.

Over the past decade, CRISPR/Cas-based gene editing has become a powerful tool for generating mutations in a variety of model organisms, from Escherichia coli to zebrafish, rodents and large mammals. CRISPR/Cas-based gene editing effectively generates insertions or deletions (indels), which allow for rapid gene disruption. However, a large proportion of human genetic diseases are caused by single-base-pair substitutions, which result in more subtle alterations to protein function, and which require more complex and precise editing to recreate in model systems. Precise genome editing (PGE) methods, however, typically have efficiencies of less than a tenth of those that generate less-specific indels, and so there has been a great deal of effort to improve PGE efficiency. Such optimisations include optimal guide RNA and mutation-bearing donor DNA template design, modulation of DNA repair pathways that underpin how edits result from Cas-induced cuts, and the development of Cas9 fusion proteins that introduce edits via alternative mechanisms. In this Review, we provide an overview of the recent progress in optimising PGE methods and their potential for generating models of human genetic disease.

Identifying Longitudinal CD4:CD8 Ratio Trajectories Indicative of Chronic Renal Disease Risk among People Living with HIV: An Application of Growth Mixture Models.

The incidence of chronic kidney disease (CKD) is increasing among people living with HIV (PLWH). Routine monitoring of indicators such as CD4:CD8 ratio might improve the early detection of CKD. Our objective was to identify clinically relevant CD4:CD8 ratio trajectories indicative of CKD risk. Participants were ≥ 18 years old, initiated antiretroviral therapy between 2000 and 2016, and were followed for ≥6 months until 31 March 2017 or last contact date. Outcome was incidence of CKD. Growth mixture models (GMMs) and decay models were used to compare CD4:CD8 ratio trajectories. Following GMM, 4547 (93.5%) participants were classified in Class 1 with 5.4% developing CKD, and 316 (6.5%) participants were classified in Class 2 with 20.9% developing CKD. The final model suggested that participants in Class 2 had 8.72 times the incidence rate of developing CKD than those in Class 1. Exponential decay models indicated a significant CD4:CD8 ratio decline among Class 2 participants who developed CKD. Among those who developed CKD in Class 2, starting at 5.5 years of follow-up, the slope of their ratio trajectory curve changed significantly, and the rate of decline increased dramatically. Routine monitored CD4:CD8 ratios can be an effective strategy to identify early CKD risk among PLWH.

Suicidal Ideation Amongst University Students During the COVID-19 Pandemic: Time Trends and Risk Factors.

OBJECTIVE: Examine time trends in suicidal ideation in post-secondary students over the first three waves of the COVID-19 pandemic in Canada and identify subpopulations of students with increased risk. METHOD: We analysed 14 months of data collected through repeated cross-sectional deployment of the World Health Organization (WHO) World Mental Health-International College Student (WMH-ICS) survey at the University of British Columbia. Estimated log odds weekly trends of 30-day suicidal ideation (yes/no) were plotted against time with adjustments for demographics using binary logistic generalized additive model (GAM). Risk factors for 30-day suicidal ideation frequency (four categories) were examined using the ordered logistic GAM, with a cubic smoothing spline for modelling time trend in obervation weeks and accounting for demographics. RESULTS: Nearly one-fifth (18.9%) of students experienced suicidal ideation in the previous 30 days. While the estimated log odds suggested that binary suicidal ideation was relatively stable across the course of the pandemic, an initial drop followed by an increasing trend was observed. Risk factors for suicidal ideation frequency during the pandemic included identifying as Chinese or as another non-Indigenous ethnic minority; experiencing current symptoms of depression or anxiety; having a history of suicidal planning or attempts; and feeling overwhelmed but unable to get help as a result of COVID-19. Older age was identified as a protective factor. CONCLUSIONS: The general university student population in our study was relatively resilient with respect to suicidal ideation during the first three waves of the pandemic, but trends indicate the possibility of delayed impact. Specific sub-populations were found to be at increased risk and should be considered for targeted support. Further analyses should be undertaken to continue monitoring suicidality trends throughout the remainder of the pandemic and beyond.