Prevalence, severity and risk factors for mental disorders among sexual and gender minority young people: a systematic review of systematic reviews and meta-analyses.

Evidence suggests heightened prevalence and severity of mental disorders among sexual minority (SM) and gender minority (GM) young people. Several risk factors have been associated with these disparities. A systematic review of systematic reviews and meta-analysis was conducted to provide a comprehensive overview of the literature and to determine the field's current position. MEDLINE, PsycInfo, Scopus and Web of Science were searched in March 2022 and updated January 2024. Eligibility criteria were systematic reviews or meta-analyses assessing contemporaneous prevalence, severity and/or risk factors of mental disorders among SM or GM young people aged 25 and under. 42 reviews were included, all of which were low quality. The prevalence of depression among SM was 26% (95% CI 21-32%), and among GM was 46% (95% CI 36-56%). Greater depression severity was found among SM compared to heterosexual young people, with a significant albeit small effect size (Hedges' g = 0.38, 95% CI = 0.25 to 0.50); effect sizes were similar when separating by gender. GM also reported greater symptom severity compared to cisgender young people. Other mental disorders were more prevalent compared to those reported in the general population, and of greater severity compared to heterosexual/cisgender young people. Several proximal and distal risk factors were focused upon within the systematic reviews identified. Past systematic reviews consistently indicate a heightened risk of mental disorders among SM and GM young people. Services need to be aware of these disparities and adapt their care accordingly.

Transcriptomic changes in single yeast cells under various stress conditions.

BACKGROUND: The stress response of Saccharomyces cerevisiae has been extensively studied in the past decade. However, with the advent of recent technology in single-cell transcriptome profiling, there is a new opportunity to expand and further understanding of the yeast stress response with greater resolution on a system level. To understand transcriptomic changes in baker's yeast S. cerevisiae cells under stress conditions, we sequenced 117 yeast cells under three stress treatments (hypotonic condition, glucose starvation and amino acid starvation) using a full-length single-cell RNA-Seq method. RESULTS: We found that though single cells from the same treatment showed varying degrees of uniformity, technical noise and batch effects can confound results significantly. However, upon careful selection of samples to reduce technical artifacts and account for batch-effects, we were able to capture distinct transcriptomic signatures for different stress conditions as well as putative regulatory relationships between transcription factors and target genes. CONCLUSION: Our results show that a full-length single-cell based transcriptomic analysis of the yeast may help paint a clearer picture of how the model organism responds to stress than do bulk cell population-based methods.

Structural Basis of Duplex Thermodynamic Stability and Enhanced Nuclease Resistance of 5'-C-Methyl Pyrimidine-Modified Oligonucleotides.

Although judicious use of chemical modifications has contributed to the success of nucleic acid therapeutics, poor systemic stability remains a major hurdle. The introduction of functional groups around the phosphate backbone can enhance the nuclease resistance of oligonucleotides (ONs). Here, we report the synthesis of enantiomerically pure (R)- and (S)-5'-C-methyl (C5'-Me) substituted nucleosides and their incorporation into ONs. These modifications generally resulted in a decrease in thermal stability of oligonucleotide (ON) duplexes in a manner dependent on the stereoconfiguration at C5' with greater destabilization characteristic of (R)-epimers. Enhanced stability against snake venom phosphodiesterase resulted from modification of the 3'-end of an ON with either (R)- or (S)-C5'-Me nucleotides. The (S)-isomers with different 2'-substituents provided greater resistance against 3'-exonucleases than the corresponding (R)-isomers. Crystal structure analyses of RNA octamers with (R)- or (S)-5'-C-methyl-2'-deoxy-2'-fluorouridine [(R)- or (S)-C5'-Me-2'-FU, respectively] revealed that the stereochemical orientation of the C5'-Me and the steric effects that emanate from the alkyl substitution are the dominant determinants of thermal stability and are likely molecular origins of resistance against nucleases. X-ray and NMR structural analyses showed that the (S)-C5'-Me epimers are spatially and structurally more similar to their natural 5' nonmethylated counterparts than the corresponding (R)-epimers.

Hepatocyte-specific delivery of siRNAs conjugated to novel non-nucleosidic trivalent N-acetylgalactosamine elicits robust gene silencing in vivo.

We recently demonstrated that siRNAs conjugated to triantennary N-acetylgalactosamine (GalNAc) induce robust RNAi-mediated gene silencing in the liver, owing to uptake mediated by the asialoglycoprotein receptor (ASGPR). Novel monovalent GalNAc units, based on a non-nucleosidic linker, were developed to yield simplified trivalent GalNAc-conjugated oligonucleotides under solid-phase synthesis conditions. Synthesis of oligonucleotide conjugates using monovalent GalNAc building blocks required fewer synthetic steps compared to the previously optimized triantennary GalNAc construct. The redesigned trivalent GalNAc ligand maintained optimal valency, spatial orientation, and distance between the sugar moieties for proper recognition by ASGPR. siRNA conjugates were synthesized by sequential covalent attachment of the trivalent GalNAc to the 3'-end of the sense strand and resulted in a conjugate with in vitro and in vivo potency similar to that of the parent trivalent GalNAc conjugate design.

Multivalent N-acetylgalactosamine-conjugated siRNA localizes in hepatocytes and elicits robust RNAi-mediated gene silencing.

Conjugation of small interfering RNA (siRNA) to an asialoglycoprotein receptor ligand derived from N-acetylgalactosamine (GalNAc) facilitates targeted delivery of the siRNA to hepatocytes in vitro and in vivo. The ligands derived from GalNAc are compatible with solid-phase oligonucleotide synthesis and deprotection conditions, with synthesis yields comparable to those of standard oligonucleotides. Subcutaneous (SC) administration of siRNA-GalNAc conjugates resulted in robust RNAi-mediated gene silencing in liver. Refinement of the siRNA chemistry achieved a 5-fold improvement in efficacy over the parent design in vivo with a median effective dose (ED50) of 1 mg/kg following a single dose. This enabled the SC administration of siRNA-GalNAc conjugates at therapeutically relevant doses and, importantly, at dose volumes of ≤1 mL. Chronic weekly dosing resulted in sustained dose-dependent gene silencing for over 9 months with no adverse effects in rodents. The optimally chemically modified siRNA-GalNAc conjugates are hepatotropic and long-acting and have the potential to treat a wide range of diseases involving liver-expressed genes.

Comprehensive evaluation of canonical versus Dicer-substrate siRNA in vitro and in vivo.

Since the discovery of RNA interference (RNAi), researchers have identified a variety of small interfering RNA (siRNA) structures that demonstrate the ability to silence gene expression through the classical RISC-mediated mechanism. One such structure, termed "Dicer-substrate siRNA" (dsiRNA), was proposed to have enhanced potency via RISC-mediated gene silencing, although a comprehensive comparison of canonical siRNAs and dsiRNAs remains to be described. The present study evaluates the in vitro and in vivo activities of siRNAs and dsiRNAs targeting Phosphatase and Tensin Homolog (PTEN) and Factor VII (FVII). More than 250 compounds representing both siRNA and dsiRNA structures were evaluated for silencing efficacy. Lead compounds were assessed for duration of silencing and other key parameters such as cytokine induction. We identified highly active compounds from both canonical siRNAs and 25/27 dsiRNAs. Lead compounds were comparable in potency both in vitro and in vivo as well as duration of silencing in vivo. Duplexes from both structural classes tolerated 2'-OMe chemical modifications well with respect to target silencing, although some modified dsiRNAs demonstrated reduced activity. On the other hand, dsiRNAs were more immunostimulatory as compared with the shorter siRNAs, both in vitro and in vivo. Because the dsiRNA structure does not confer any appreciable benefits in vitro or in vivo while demonstrating specific liabilities, further studies are required to support their applications in RNAi therapeutics.

Transcriptomic analysis of the spatiotemporal axis of oogenesis and fertilization in C. elegans.

Caenorhabditis elegans hermaphrodite presents a unique model to study the formation of oocytes. However, the size of the model animal and difficulties in retrieval of specific stages of the germline have obviated closer systematic studies of this process throughout the years. Here, we present a transcriptomic level analysis into the oogenesis of C. elegans hermaphrodites. We dissected a hermaphrodite gonad into seven sections corresponding to the mitotic distal region, the pachytene region, the diplotene region, the early diakinesis region and the 3 most proximal oocytes, and deeply sequenced the transcriptome of each of them along with that of the fertilized egg using a single-cell RNA-seq (scRNA-seq) protocol. We identified specific gene expression events as well as gene splicing events in finer detail along the gonad and provided novel insights into underlying mechanisms of the oogenesis process. Furthermore, through careful review of relevant research literature coupled with patterns observed in our analysis, we delineate transcripts that may serve functions in the interactions between the germline and cells of the somatic gonad. These results expand our knowledge of the transcriptomic space of the C. elegans germline and lay a foundation on which future studies of the germline can be based upon.

Transcriptomic Analysis of the Spatiotemporal Axis of Oogenesis and Fertilization in C. elegans.

The oocyte germline of the C. elegans hermaphrodite presents a unique model to study the formation of oocytes. However, the size of the model animal and difficulties in retrieval of specific stages of the germline have obviated closer systematic studies of this process throughout the years. Here, we present a transcriptomic level analysis into the oogenesis of C. elegans hermaphrodites. We dissected a hermaphrodite gonad into seven sections corresponding to the mitotic distal region, the pachytene, the diplotene, the early diakinesis region and the 3 most proximal oocytes, and deeply sequenced the transcriptome of each of them along with that of the fertilized egg using a single-cell RNA-seq protocol. We identified specific gene expression events as well as gene splicing events in finer detail along the oocyte germline and provided novel insights into underlying mechanisms of the oogenesis process. Furthermore, through careful review of relevant research literature coupled with patterns observed in our analysis, we attempt to delineate transcripts that may serve functions in the interaction between the germline and cells of the somatic gonad. These results expand our knowledge of the transcriptomic space of the C. elegans germline and lay a foundation on which future studies of the germline can be based upon.

Prevalence, severity and risk factors of psychiatric disorders amongst sexual and gender diverse young people during the COVID-19 pandemic: A systematic review.

Before the COVID-19 pandemic, the prevalence and severity of psychiatric disorders among sexual and gender diverse (SGD) young people was greater than in their heterosexual/cisgender peers. We systematically reviewed literature examining the prevalence, severity, and risk factors for psychiatric disorders among SGD young people aged 25 and under during the pandemic. Four databases (MEDLINE, PsycInfo, Scopus and Web of Science) were searched. Eligibility criteria were studies assessing prevalence rates, mean symptomology scores and risk factors of psychiatric disorders using contemporaneous screening measures or diagnosis. Thirteen studies of mixed quality were identified. Most studies indicated SGD young people were at high risk of experiencing several psychiatric disorders including depressive and generalised anxiety disorder compared to the general population. This group also experienced more severe symptomology of various psychiatric disorders compared to their heterosexual/cisgender peers. Risk factors included those specific to the pandemic along with factors that led to greater risk before the pandemic. This systematic review has indicated evidence of heightened risk of psychiatric disorders among SGD young people during the COVID-19 pandemic. It is important for clinicians to acknowledge the needs of SGD young people, working with them to co-develop more inclusive care as they deal with the pandemic's fallout.

Why was the study done?Before the COVID-19 pandemic, the prevalence and severity of psychiatric disorders in sexual and gender diverse (SGD) young people was greater than in their heterosexual/cisgender peers, based on several risk factors. Research using validated screening measures assessed whether this continued during the pandemic. Yet, these studies have not been brought together in an organised fashion to provide a comprehensive summary of this evidence.What did the researchers do?We reviewed literature examining the prevalence, severity, and risk factors for psychiatric disorders among SGD young people aged 25 and under during the pandemic. Eligibility criteria were studies assessing prevalence rates, mean symptomology scores or risk factors of psychiatric disorders using contemporaneous screening measures or diagnosis.What did the researchers find?Thirteen studies of mixed quality were identified. Most studies indicated SGD young people were more likely to report experiencing several psychiatric disorders including depressive and generalised anxiety disorders compared to the general population. SGD young people also experienced more severe symptomology of various psychiatric disorders compared to their heterosexual/cisgender peers. Risk factors included those specific to the pandemic along with factors that existed before the pandemic.What do the findings mean?This review suggests SGD young people were at greater risk of psychiatric disorders during the COVID-19 pandemic. Clinicians should acknowledge the needs of SGD young people, working with them to co-develop more inclusive care as they deal with the pandemic's fallout.

Physical health complications in children and young people with avoidant restrictive food intake disorder (ARFID): a systematic review and meta-analysis.

BACKGROUND: Avoidant restrictive food intake disorder (ARFID) is a feeding and eating disorder with known acute and longstanding physical health complications in children and young people (CYP) and commonly presents to paediatricians. OBJECTIVE: To systematically review the published literature on physical health complications in CYP with ARFID using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. METHODS: A systematic search of PubMed, Embase, Web of Science, PsycINFO and Cochrane Library was performed on 14 February 2024. Studies reporting physical health complications in CYP ≤25 years with ARFID were included. We pooled studies for meta-analysis comparing ARFID with healthy controls or anorexia nervosa (AN). RESULTS: Of 9058 studies found in searches, we included 132 studies. We found evidence for low weight, nutritional deficiencies and low bone mineral density. CYP with ARFID can present across the weight spectrum; however, the majority of CYP with ARFID were within the healthy weight to underweight range. Most studies reported normal range heart rates and blood pressures in ARFID, but some CYP with ARFID do experience bradycardia and hypotension. CYP with ARFID had higher heart rates than AN (weighted mean difference: 12.93 bpm; 95% CI: 8.65 to 17.21; n=685); heterogeneity was high (I2: 81.33%). CONCLUSION: There is a broad range of physical health complications associated with ARFID requiring clinical consideration. Many CYP with ARFID are not underweight yet still have complications. Less cardiovascular complications found in ARFID compared with AN may be related to chronicity. PROSPERO REGISTRATION NUMBER: CRD42022376866.

Choline metabolites and incident cardiovascular disease in a prospective cohort of adults: Coronary Artery Risk Development in Young Adults (CARDIA) Study.

BACKGROUND: The potential role for choline metabolite trimethylamine N-oxide (TMAO) in cardiovascular disease (CVD) has garnered much attention, but there have been limited data from diverse population-based cohorts. Furthermore, few studies have included circulating choline and betaine, which can serve as precursors to TMAO and may independently influence CVD. OBJECTIVE: We quantified prospective associations between 3 choline metabolites and 19-y incident CVD in a population-based cohort and tested effect modification of metabolite-CVD associations by kidney function. METHODS: Data were from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a prospective cohort with recruitment from 4 US urban centers (year 0: 1985-1986, n = 5115, ages 18-30). The analytic sample included 3444 White and Black males and females, aged 33 to 45, who attended the year 15 follow-up exam and did not have prevalent CVD. TMAO, choline, and betaine were quantitated from stored plasma (-70°C) using liquid-chromatography mass-spectrometry. Nineteen-year incident CVD events (n = 221), including coronary heart disease and stroke, were identified through adjudicated hospitalization records and linkage with the National Death Register. RESULTS: Plasma choline was positively associated with CVD in Cox proportional hazards regression analysis adjusted for demographics, health behaviors, CVD risk factors, and metabolites (hazard ratio: 1.24; 95% CI: 1.09, 1.40 per standard deviation-unit choline). TMAO and betaine were not associated with CVD in an identically adjusted analysis. There was statistical evidence for effect modification by kidney function with CVD positively associated with TMAO and negatively associated with betaine at lower values of estimated glomerular filtration rate (interaction P values: 0.0046 and 0.020, respectively). CONCLUSIONS: Our findings are consistent with a positive association between plasma choline and incident CVD. Among participants with lower kidney function, TMAO was positively, and betaine negatively, associated with CVD. These results further our understanding of the potential role for choline metabolism on CVD risk.

Metabolically Stable Anomeric Linkages Containing GalNAc-siRNA Conjugates: An Interplay among ASGPR, Glycosidase, and RISC Pathways.

Conjugation of synthetic triantennary N-acetyl-d-galactosamine (GalNAc) to small interfering RNA (siRNA) mediates binding to the asialoglycoprotein receptor (ASGPR) on the surface of hepatocytes, facilitating liver-specific uptake and siRNA-mediated gene silencing. The natural ß-glycosidic bond of the GalNAc ligand is rapidly cleaved by glycosidases in vivo. Novel GalNAc ligands with S-, and C-glycosides with both α- and ß-anomeric linkages, N-glycosides with ß-anomeric linkage, and the O-glycoside with α-anomeric linkage were synthesized and conjugated to siRNA either on-column during siRNA synthesis or through a high-throughput, post-synthetic method. Unlike natural GalNAc, modified ligands were resistant to glycosidase activity. The siRNAs conjugated to newly designed ligands had similar affinities for ASGPR and similar silencing activity in mice as the parent GalNAc-siRNA conjugate. These data suggest that other factors, such as protein-nucleic acid interactions and loading of the antisense strand into the RNA-induced silencing complex (RISC), are more critical to the duration of action than the stereochemistry and stability of the anomeric linkage between the GalNAc moiety of the ligand conjugated to the sense strand of the siRNA.

Discovery of a novel deaminated metabolite of a single-stranded oligonucleotide in vivo by mass spectrometry.

Aim: A novel single-stranded deaminated oligonucleotide metabolite resulting from a REVERSIR™ oligonucleotide was discovered and identified in monkey liver after subcutaneous administration. Results & methodology: REVERSIR-A and its metabolites were extracted from biological matrices by solid phase extraction and analyzed using LC coupled with high-resolution MS under negative ionization mode. A novel 9-mer metabolite of REVERSIR-A, resulting from deamination of the 3' terminal 2'-O-methyl-adenosine nucleotide to 2'-O-methyl-inosine, was discovered at significant levels in monkey liver. The metabolite's identity was confirmed by LC-MS/MS. Conclusion: This report describes the first observation of a long-chain deaminated metabolite of a single-stranded REVERSIR oligonucleotide in vivo in monkey liver.

Dietary Choline and Betaine and Risk of CVD: A Systematic Review and Meta-Analysis of Prospective Studies.

Studies implicate choline and betaine metabolite trimethylamine N-oxide (TMAO) in cardiovascular disease (CVD). We conducted a systematic review and random-effects meta-analysis to quantify a summary estimated effect of dietary choline and betaine on hard CVD outcomes (incidence and mortality). Eligible studies were prospective studies in adults with comprehensive diet assessment and follow-up for hard CVD endpoints. We identified six studies that met our criteria, comprising 18,076 incident CVD events, 5343 CVD deaths, and 184,010 total participants. In random effects meta-analysis, incident CVD was not associated with choline (relative risk (RR): 1.00; 95% CI: 0.98, 1.02) or betaine (RR: 0.99; 95% CI: 0.98, 1.01) intake. Results did not vary by study outcome (incident coronary heart disease, stroke, total CVD) and there was no evidence for heterogeneity among studies. Only two studies provided data on phosphatidylcholine and CVD mortality. Random effects meta-analysis did not support an association between choline and CVD mortality (RR: 1.09, 95% CI: 0.89, 1.35), but one study supported a positive association and there was significant heterogeneity (I² = 84%, p-value < 0.001). Our findings do not support an association between dietary choline/betaine with incident CVD, but call for further research into choline and CVD mortality.