Abstract The teleost pineal gland is an eye-like photoreceptive organ with a central role in the circadian clock system, primarily through its melatonin-producing photoreceptor cells. However, the functional molecular interactions between pineal photoreceptors, accessory cells predicted to support photoreceptor function, and projecting neurons remain incompletely understood. Here, we integrated single-cell zebrafish pineal transcriptomes with bulk circadian and light-response pineal transcriptomes. Combined analysis of two single-cell datasets identified novel photoreceptor and neuronal subtypes, including parietopsin -expressing cone-like cells and neurons expressing markers of neuronal maturation. Integration with the light-response dataset revealed light inhibition of photoreceptor opsin genes. Integration with circadian transcriptomes from wildtype fish and fish expressing the clock-disrupting dominant-negative CLOCK (ΔCLK) in pineal photoreceptors revealed cell-type-specific rhythmicity. Despite comparable expression of ΔCLK, photoreceptor subtypes differed in sensitivity to rhythm disruption, with rod-like cells (rods) most severely affected. In neurons, despite the absence of ΔCLK expression, rhythm disruption was comparable to that of rods. Moreover, rhythmic neuronal markers and rhythmic photoreceptor markers exhibited a similar circadian pattern, peaking mainly during the early night. These observations suggest that clock function in neurons depend on photoreceptor output. In contrast, accessory cell rhythmic markers were relatively resistant to ΔCLK disruption and peaked predominantly around subjective dawn, consistent with partially autonomous clock function. To facilitate comparative analysis of gene expression, rhythmicity and light responsiveness across pineal cell types, we developed the Zebrafish Pineal Transcriptomics Viewer. Our findings reveal a temporally structured and functionally heterogeneous organization of the zebrafish pineal gland.

Cortical gyrification is a key marker of fetal brain development and is typically assessed qualitatively on ultrasound or MRI. While previous quantitative approaches have characterized gestational trajectories in typically developing (TD) fetuses, only a few studies have investigated cortical malformations such as lissencephaly and polymicrogyria. Spectral analysis, which characterizes signals by their frequency content, has been successfully applied to study gyrification in neonates and adults but has not yet been explored prenatally. This study aimed to apply spectral analysis to routine fetal MRI to quantitatively assess cortical gyrification, characterize gestational age-related patterns in TD fetuses, and compare gyrification across TD, lissencephaly and polymicrogyria fetuses. Cerebral contours were extracted from coronal slices, transformed into polar coordinates, and analyzed using Fourier transform to derive spectral profiles including five gyrification features based on the overall spectral power: spectral density, entropy, mean frequency, variance, and skewness as well as the first twelve frequencies. Seventy-three TD fetuses and twenty-four with malformations of cortical development (10 lissencephaly, 14 polymicrogyria) were evaluated across gestation. Differences between TD, lissencephaly, or polymicrogyria fetuses were evaluated using linear mixed models and post-hoc t-tests with Benjamini–Hochberg correction. In TD fetuses, spectral features showed gestational-age–related trajectories in most features and frequencies, corresponding to the sequential folding waves. Fetuses with cortical malformations had lower spectral density and entropy (p ≤ 0.031), and reduced amplitudes across most of the twelve frequencies, most prominently in frequencies associated with the Sylvian fissure (p < 0.001) compared with TD fetuses, with significant greater reductions in lissencephaly compared with polymicrogyria. Spectral representation may capture global cortical folding as well as distinct spectral patterns, offering a robust and quantitative biomarker of fetal brain maturation and deviations in cortical development.

INTRODUCTION:Placental insufficiency is a major cause of fetal growth restriction (FGR), yet current in-vivo imaging methods for placental assessment are limited. MRI-based placental biomarkers may provide a promising tool to identify fetuses at risk. This study aims to evaluate placental morphology using in-vivo MRI in third-trimester fetuses, identify structural features associated with gestational-age (GA) and growth outcomes, and identify features that differentiate appropriate-for-GA (AGA) from FGR-complicated fetuses. METHODS:A total of 141 participants (102 AGA and 39 FGR due to placental insufficiency) were scanned between 30 + 0 and 37 + 2 weeks of gestation using 3T MRI True Fast Imaging with Steady-State Free Precession sequence. Seventeen morphological features were extracted, including umbilical cord insertion location, quantified as the centricity index (CI), placental volume, shape, maternal and fetal surface areas, along with fetal body and birthweight measures. Inter-observer agreement for CI was assessed with Intraclass correlation. Associations between placental morphology, GA, and growth outcomes were evaluated using Spearman's correlation. Group differences were tested with Mann-Whitney U and Benjamini-Hochberg correction (p < 0.05). RESULTS:In AGA, placental elongation increased with GA (r = -0.238). Placental volume, minor axis length, maximum 2D diameter, and surface areas correlated with growth outcomes (r = 0.21-0.40). In FGR, placental volume and surface areas were correlated with GA (r = 0.32-0.38). Placental volume remained associated with growth outcomes, and CI with birthweight percentiles (r = 0.34-0.60). FGR placentas exhibited marginal cord insertions, smaller size measures, and higher surface-to-volume ratio. DISCUSSION:MRI-derived placental morphology shows alterations in FGR and associations with growth outcomes, supporting identification of at-risk fetuses.

Fetal fat accretion follows a spatiotemporal pattern. Fetuses who are small-for-gestational-age (SGA) demonstrate reduced fat accumulation, but whether specific body regions are disproportionately affected remains unclear. To characterize regional fat differences between SGA and appropriate-for-gestational-age (AGA), assess the modifying effects of SGA-onset timing and cerebroplacental ratio (CPR), and evaluate associations with neonatal morbidity. SGA pregnancies were prospectively recruited, and AGA controls retrospectively identified. SGA was defined as estimated fetal weight <10th centile and classified as early-onset (< 32 weeks) or late-onset (≥ 32 weeks), with CPR categorized as normal (≥ 5th centile) or abnormal (< 5th centile). Fetal Magnetic resonance imaging was performed at 3-T using T1-weighted two-point Dixon. Subcutaneous fat was segmented and subdivided into cheeks, trunk, upper and lower limbs. Fat signal fraction and fat mass were computed, with regional fat mass adjusted to global fat mass. Linear mixed models compared groups, and univariate logistic regression assessed associations with adverse outcomes. Sixty-four participants (35 SGA, 29 AGA) were included. Fat signal fraction was significantly lower in SGA across all regions (P<0.001). Upper limb adjusted fat mass was reduced in SGA (P=0.043), while other regions showed no differences (P≥0.08). Fat signal fraction and adjusted fat mass did not differ by SGA onset or CPR status. Lower fat signal fraction in all regions was associated with higher morbidity rates, whereas adjusted fat mass was not. SGA fetuses exhibit globally reduced lipid content with a disproportionate upper limb fat mass deficit, suggesting selective vulnerability of peripheral fat depots.

OBJECTIVE:Quantitative assessment of the impact of cytomegalovirus (CMV) infection on fetal brain development beyond conventional imaging remains limited. We aimed to quantify cortical gyrification and brain volumes in CMV-exposed fetuses, compare groups with varying severities of conventional MRI findings, and evaluate postnatal outcomes. METHOD:This retrospective study included 82 singleton pregnancies following maternal CMV infection. Fetuses were grouped by CMV infection status and conventional MRI findings. Automated tools quantified cerebral gyrification and supratentorial, infratentorial and lateral ventricle volumes. Postnatal hearing and neurodevelopmental outcomes were assessed at follow-up. RESULTS:CMV-infected fetuses (n = 67) showed reduced cerebral gyrification compared with uninfected controls (n = 15). This reduction was observed across fetuses with gross (n = 10), subtle (n = 19), and even normal (n = 38) MRI findings. Infected fetuses with gross abnormalities also showed reduced infratentorial volume compared with infected fetuses with normal MRI and controls. Follow-up was available in 42 cases and indicated that most children developed normally. However, eight children developed mild-to-moderate neurodevelopmental difficulties, four of whom also had sensorineural hearing loss, including cases with normal or subtle prenatal imaging. CONCLUSION:Quantitative analysis of routine fetal MRI reveals alterations in brain development in CMV-infected fetuses, including those with normal conventional imaging, and may improve the identification of fetuses at risk for adverse outcomes.

Adequate placental structure and function are crucial for fetal growth, while placental dysfunction often leads to fetal growth restriction (FGR), associated with increased perinatal morbidity and mortality. Current FGR criteria, relying on sonographic biometry and Doppler assessments, typically fall short in sensitivity for diagnosing FGR, predicting perinatal outcomes, and assessing their association with placental pathology. Advanced MRI methods offer a unique opportunity to characterize placental structure and perfusion, and to assess their relationship with fetal growth. This study aims to provide normative quantitative MRI values of placental structure and perfusion during the third trimester, to assess their interplay and association with fetal growth, and to identify differences between appropriate-for-gestational-age (AGA) and FGR-complicated pregnancies. With IRB approval, pregnant women between 30 and 37 weeks of gestation (AGA [n = 46], FGR [n = 11]) underwent prospective MRI. Placental structure (volume; umbilical-cord centricity-index [CI]), placental perfusion (placental-blood-flow [PBF] and arterial-transit-time [ATT] extracted from arterial-spin-labeling), fetal growth (estimated body weight and brain volume), and radiomics features derived from PBF and ATT maps were assessed using deep-learning and image-processing tools. Statistical analyses included Pearson correlation, analysis of covariance with gestational-age (GA) as a covariate, non-parametric tests, logistic regression, multistep feature selection, and false discovery rate correction. Fetal growth parameters correlated with GA in both groups and were significantly reduced in FGR. Mean perfusion values of AGA placentas were significantly higher than previously reported at earlier GA using the same method. Placental volume correlated with ATT and total placental flow (mean PBF × placental volume/100) in AGA fetuses. Total placental flow was significantly lower in FGR compared with AGA. CI and two ATT radiomics features contributed most to differentiating AGA from FGR, with higher CI in FGR. Our findings highlight CI as a potential marker for growth restriction. Larger studies are needed to better characterize perfusion alterations in FGR.

ATAD3A, a nuclear gene encoding the ATAD3A protein, has diverse roles in mitochondrial processes, encompassing mitochondrial dynamics, mitochondrial DNA maintenance, metabolic pathways and inter-organellar interactions. Pathogenic variants in this gene cause neurological diseases in humans with recognizable genotype-phenotype correlations. Yet, gaps in knowledge remain regarding the underlying pathogenesis. To further investigate the gene function and its implication in health and disease, we utilized CRISPR/Cas9 genome editing to generate a knockout model of the zebrafish ortholog gene, atad3. We characterized the phenotype of the null model, performed mitochondrial and functional tests, and compared the transcriptome of null embryos to their healthy siblings. Analysis of atad3-null zebrafish embryos revealed microcephaly, small eyes, pericardial edema and musculature thinning, closely mirroring the human rare disease phenotype. Larvae exhibited delayed hatching and embryonic lethality by 13 days post-fertilization (dpf). Locomotor activity, ATP content, mitochondrial content, and mitochondrial activity were all reduced in the mutant embryos. Transcriptome analysis at 3 dpf via RNA-sequencing indicated decline in most mitochondrial pathways, accompanied by a global upregulation of cytosolic tRNA synthetases, presumably secondary to mitochondrial stress and possibly endoplasmic reticulum (ER)-stress. Differential expression of select genes was corroborated in fibroblasts from an affected individual. The atad3-null zebrafish model emerges as a reliable representation of human ATAD3A-associated disorders, with similarities in differentially expressed pathways and processes. Furthermore, our study underscores mitochondrial dysfunction as the primary underlying pathogenic mechanism in ATAD3A-associated disorders and identifies potential readouts for therapeutic studies.

Precise regulation of RNA polymerase II (RNAPII) is fundamental to transcriptional fidelity in eukaryotes. The Integrator complex, a conserved multi-subunit assembly, safeguards transcriptional integrity through its interaction with RNAPII, mediating transcription initiation and termination by nascent RNA cleavage and 3' end processing. INTS1, the largest subunit of the Integrator complex, is critical for its function, and its mutations are linked to human neurodevelopmental disorders, yet the underlying transcriptional effects remain poorly defined. Here, we characterize the global transcriptional effects of INTS1 deficiency in zebrafish. INTS1 loss leads to widespread gene expression changes, including genes linked to hyperactivity and pathways associated with attention-deficit/hyperactivity disorder. We observe mutant-specific first intron retentions and transcript extensions. These findings underscore a central role for INTS1 in coordinating transcriptional regulation and highlight the essential function of the Integrator complex in maintaining transcriptome integrity. Together, they offer insights into how INTS1 disruption may contribute to behavioral and physiological abnormalities.

Cortical gyrification is a key marker of fetal brain development and is typically assessed qualitatively on ultrasound or MRI. While previous quantitative approaches have characterized gestational trajectories in typically developing (TD) fetuses, only a few studies have investigated cortical malformations such as lissencephaly and polymicrogyria. Spectral analysis, which characterizes signals by their frequency content, has been successfully applied to study gyrification in neonates and adults but has not yet been explored prenatally. In this study, we introduce a spectral framework for quantifying fetal cortical folding from routine fetal MRI. Cerebral contours were extracted from coronal slices, transformed into polar coordinates, and analyzed using Fourier Transform to derive spectral profiles and five gyrification features: non-zero spectral density, entropy, mean frequency, variance, and skewness and the first twelve frequencies. Seventy-three TD fetuses and twenty-four with malformations of cortical development (14 polymicrogyria, 10 lissencephaly) were evaluated across gestation. Differences between TD, lissencephaly, or polymicrogyria fetuses were evaluated using linear mixed models and post-hoc t-tests with Benjamini–Hochberg correction. In TD fetuses, spectral features showed gestational-age–related trajectories, with increasing spectral density and variance and decreasing skewness, corresponding to the sequential folding waves. Fetuses with cortical malformations had lower spectral density and entropy ( p ≤ 0.031), and reduction in most of the twelve frequencies, most prominently in frequencies associated with the Sylvian fissure development ( p < 0.001). Spectral representation may capture both global and local aspects of cortical folding, offering a robust and quantitative biomarker of fetal brain maturation and deviations in cortical development.

Nanoplastics (NPs) pose emerging risks to both the environment and human health. In this study, we use a zebrafish in vivo model to study-and compare-the physicochemical and toxicological effects of two distinct polystyrene NPs: widely used commercial polymeric nanobeads and nanoscale simulated environmental plastics (SEPs) engineered using a top-down accelerated weathering protocol. Zebrafish embryos and larvae exposed to NPs were assessed for changes in development, growth, locomotor activity, and stress and hypoxic responses. SEP-besides being more environmentally relevant than the commercial nanobeads-significantly delayed hatching and reduced body length (up to 150 mu m shorter) compared to the minor effects of the nanobeads at the same concentrations. Moreover, SEPs impaired locomotor activity (40% reduction in distance traveled) and triggered a dose-dependent stress response, increasing cortisol levels (2-3 fold) and upregulating stress and hypoxia-related genes. The stress-related condition induced by SEP exposure, observed throughout the study, involved alterations in the hypothalamic-pituitary-adrenal-interrenal (HPA/HPI) axis, particularly in glucocorticoid signaling (i.e., cortisol), which plays a crucial role in regulating stress responses and developmental processes. These alterations could potentially influence the development and adult life of living organisms, including the onset of associated pathologies. Furthermore, these findings underscore significant ecological and health risks, as even low concentrations of NPs in aquatic ecosystems may impair fish populations and biodiversity while also presenting potential human health hazards through the contamination of water sources and seafood. Notably, all reported effects occurred at a relatively low concentration (0.1 mu g/L), emphasizing the need for rigorous NP risk assessment and the importance of selecting an appropriate and environmentally relevant experimental model.

Background:Fetal growth restriction (FGR) is associated with adverse perinatal outcomes. Existing sonographic approaches offer limited predictive accuracy. Combining fetal MRI, ultrasound and clinical data may improve perinatal prognostication. Purpose:To evaluate whether integrating prenatal MRI, ultrasound, and clinical features using machine learning (ML) improves prediction of adverse perinatal outcomes in FGR or small-for-gestational-age (SGA) pregnancies. Materials and Methods:This single-center study included prospectively enrolled FGR/SGA and retrospectively included appropriate-for-gestational-age cases, with follow-up through neonatal discharge. Twenty-seven features from MRI, ultrasound, and clinical data were used in the final analysis. Seven ML classifiers were trained using stratified 5-fold cross-validation to predict composite adverse neonatal outcomes (CANO) and non-reassuring fetal status (NRFS). Sensitivity and specificity of the top-performing model (based on area under the curve [AUC]) were compared to standard biometric thresholds (estimated fetal weight and/or abdominal circumference <10th/<3rd centiles). Multiparametric, MRI-only, and ultrasound-only models were compared, along with reduced models using 4 features for CANO and 2 for NRFS. Results:One hundred thirty-one participants were included (60 FGR/SGA, 71 appropriate-for-gestational-age). The random forest method achieved the highest AUC for predicting CANO (0.912; 95% confidence interval [CI], 0.83-0.99) and NRFS (0.834; 95% CI, 0.76-0.91). For CANO, the multiparametric model demonstrated a 25% higher sensitivity (P = 0.005) and 17% higher specificity (P < 0.001) compared with the 3rd centile threshold, and improved specificity over the 10th centile threshold by 29% (P < 0.001). Sensitivity did not differ significantly from the 10th centile threshold (P = 0.366). For NRFS, specificity increased by 26% and 40% over the 3rd and 10th centile thresholds, respectively (P < 0.001), without significant differences in sensitivity (P = 1). No statistically significant differences were observed between the multiparametric, ultrasound-only, and MRI-only models (P ≥ 0.826), or between full and reduced models (P ≥ 0.313). Conclusions:ML-based models integrating multimodal data may improve risk stratification for predicting adverse perinatal outcomes in FGR/SGA pregnancies.

INTRODUCTION:Examining the safety of theBNT162b2 mRNA vaccine in multiple sclerosis (MS) patients remains inconclusive, particularly regarding the potential for disease exacerbations. This study aims to assess the effects of BNT162b2 COVID-19 vaccination on disease activity in MS patients through sequential MRI imaging. METHODS:A retrospective study of 84 MS patients from five Israeli hospitals was conducted. MS lesion load was determined from three brain MRI scans, one postvaccination and two prevaccination scans. A post hoc analysis compared subgroups featuring vaccinated and unvaccinated patients respectively, with early onset MS. RESULTS:The cohort included 70 women with early onset (mean age 16.4 ± 0.8 years) and adult onset (mean age 34.9 ± 1.1 years) MS. Among the early onset group, vaccinated patients showed an increased risk of new lesions (p = .00026), while there was no increased risk among adult-onset patients. Additionally, a comparison between early onset vaccinated and nonvaccinated groups revealed a higher risk of increased lesions in the vaccinated group (p = .024). DISCUSSION:Overall, the study suggests that the BNT162b2 vaccine is generally safe in MS patients, with no association found between vaccination and new lesions in most patients. However, close MRI follow-up is recommended for early-onset MS cases to monitor lesion development.

ABSTRACT Sleep disturbances are common among children with neurodevelopmental disorders. Here, we report a syndrome characterized by prenatal microcephaly, intellectual disability and severe disruption of sleep–wake cycles in a consanguineous family. Exome sequencing revealed homozygous variants (c.5224G>A and c.6506G>T) leading to the missense mutations E1742K and G2169V in integrator complex subunit 1 (INTS1), the core subunit of the Integrator complex. Conservation and structural analyses suggest that G2169V has a minor impact on the structure and function of the complex, while E1742K significantly alters a negatively charged conserved patch on the surface of the protein. The severe sleep–wake cycles disruption in human carriers highlights a new aspect of Integrator complex impairment. To further study INTS1 pathogenicity, we generated Ints1-deficient zebrafish lines. Mutant zebrafish larvae displayed abnormal circadian rhythms of locomotor activity and sleep, as is the case with the affected humans. Furthermore, Ints1-deficent larvae exhibited elevated levels of dopamine β-hydroxylase (dbh) mRNA in the locus coeruleus, a wakefulness-inducing brainstem center. Altogether, these findings suggest a significant, likely indirect, effect of INTS1 and the Integrator complex on maintaining circadian rhythms of locomotor activity and sleep homeostasis across vertebrates.

Located dorsally underneath a thin translucent skull in many teleosts, the pineal gland is a photoreceptive organ known as a key element of the circadian clock system. Nevertheless, the presence of additional routes of photoreception presents a challenge in determining its specific roles in regulating photic-related behavior. Here, we show the importance of the pineal gland in mediating a prolonged motor response of zebrafish larvae to sudden darkness, both as a photodetector and as a circadian pacemaker. This was evident by a reduced motor response of Bsx-deficient larvae, lacking a pineal gland, to sudden darkness. Moreover, the typical daily rhythm of the intensity of this response was lost in the pineal-less larvae. In contrast, motor response to a sudden increase in illumination was unaffected. Furthermore, we show that the pineal-mediated behavioral response to darkness requires two elements: the photoreceptor cells and the projecting neurons. Dark response was impaired in larvae whose pineal photoreceptor cells were genetically ablated and in larvae whose pineal projecting neurons had undergone laser-axotomy. This study thus establishes the pineal gland as a mediator of dark-dependent behavior and reveals underlying cellular components involved in transducing information about darkness to the brain.

BACKGROUND:The American Academy of Pediatrics advises that the nutrition of preterm infants should target a body composition similar to that of a fetus in utero. Still, reference charts for intrauterine body composition are missing. Moreover, data on sexual differences in intrauterine body composition during pregnancy are limited. OBJECTIVES:The objective of this study was to create reference charts for intrauterine body composition from 30 to 36+6 weeks postconception and to evaluate the differences between sexes. METHODS:In this single-center retrospective study, data from 197 normal developing fetuses in late gestation was acquired at 3T magnetic resonance imaging (MRI) scans, including True Fast Imaging with Steady State Free Precession and T1-weighted 2-point Dixon sequences covering the entire fetus. Deep convolutional neural networks were utilized to automatically segment the fetal body and subcutaneous adipose tissue. The fetus's body mass (BM), fat signal fraction (FSF), fat mass (FM), FM percentage (FM%), fat-free mass (FFM), and FFM percentage (FFM%) were calculated. Using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) method, reference charts were created, and sexual dimorphism was examined using analysis of covariance (ANCOVA). A P value <0.05 was deemed significant. RESULTS:Throughout late gestation, BM, FSF, FM, FM%, and FFM increased, while the FFM% decreased. Reference charts for gestational age and sex-specific percentiles are provided. Males exhibited significantly higher BM (7.2%; 95% confidence interval [95% CI]: 1.9, 12.4), FFM (8.8%; 95% CI: 5.8, 11.9), and FFM% (1.7%; 95% CI: 1, 2.4) and lower FSF (-3.6%; 95% CI: -5.6, -1.8) and FM% (-1.7%; 95% CI: -2.4, -1), (P < 0.001) compared with females, with no significant difference in FM between sexes (P = 0.876). CONCLUSIONS:MRI-derived intrauterine body composition growth charts are valuable for tracking growth in preterm infants. This study demonstrated that sexual differences in body composition are already present in the intrauterine phase.

Placental-related fetal growth restriction, resulting from placental dysfunction, impacts 3-5% of pregnancies and is linked to elevated risk of adverse neurodevelopmental outcomes. In response, the fetus employs a mechanism known as brain-sparing, redirecting blood flow to the cerebral circuit, for adequate supply to the brain. In this study we aimed to quantitatively evaluate disparities in gyrification and brain volumes among fetal growth restriction, small for gestational age and appropriate-for gestational-age fetuses. Additionally, we compared fetal growth restriction fetuses with and without brain-sparing. The study encompassed 106 fetuses: 35 fetal growth restriction (14 with and 21 without brain-sparing), 8 small for gestational age, and 63 appropriate for gestational age. Gyrification, supratentorial, and infratentorial brain volumes were automatically computed from T-2-weighted magnetic resonance images, following semi-automatic brain segmentation. Fetal growth restriction fetuses exhibited significantly reduced gyrification and brain volumes compared to appropriate for gestational age (P < 0.001). Small for gestational age fetuses displayed significantly reduced gyrification (P = 0.038) and smaller supratentorial volume (P < 0.001) compared to appropriate for gestational age. Moreover, fetal growth restriction fetuses with BS demonstrated reduced gyrification compared to those without BS (P = 0.04), with no significant differences observed in brain volumes. These findings demonstrate that brain development is affected in fetuses with fetal growth restriction, more severely than in small for gestational age, and support the concept that vasodilatation of the fetal middle cerebral artery reflects more severe hypoxemia, affecting brain development.

IntroductionThe presence of oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) is a pivotal diagnostic marker for multiple sclerosis (MS). These bands play a crucial role in the diagnosis and understanding of a wide array of immune diseases. In this study, we explore the relationship between the cognitive profile of autoimmune encephalitis (AIE) and the presence of OCBs in CSF, with a particular emphasis on NMDA receptor antibodies.MethodsWe studied a cohort of 21 patients across five tertiary centers, segregated into two distinct categories. One group comprised individuals who tested positive only for autoimmune encephalitis antibodies indicative of encephalitis, while the other group included patients whose CSF was positive for both autoimmune encephalitis antibodies and OCBs. Our investigation focused primarily on cognitive functions and behavioral alterations, supplemented by auxiliary diagnostic assessments such as CSF cell count, magnetic resonance imaging (MRI), and electroencephalogram (EEG) results, evaluated for the two patient groups. To validate our findings, we employed statistical analyses such as Fisher’s exact test with Benjamini-Hochberg correction.ResultsOur study included 21 patients, comprising 14 who were presented with only autoimmune encephalitis antibodies, and 7 who were dual-positive. Among these patients, we focused on those with NMDA receptor antibodies. Of these, five were dual positive, and nine were positive only for NMDA receptor antibodies. The dual-positive NMDA group, with an average age of 27 ± 16.47 years, exhibited significantly higher CSF cell counts (p=0.0487) and more pronounced language and attention deficits (p= 0.0264). MRI and EEG results did not differ significantly between the groups.ConclusionsOur results point to OCBs as an additional marker of disease severity in AIE, especially in NMDA receptor-antibody positive patients, possibly indicating a broader inflammatory process, as reflected in elevated CSF lymphocytes. Regular testing for OCBs in cases of suspected AIE may aid in disease prognosis and identification of patients more prone to language and attention disorders, improving diagnosis and targeting treatment for these cognitive aspects.

Photoreceptors in the vertebrate eye are dependent on the retinal pigmented epithelium for a variety of functions including retinal re-isomerization and waste disposal. The light-sensitive pineal gland of fish, birds, and amphibians is evolutionarily related to the eye but lacks a pigmented epithelium. Thus, it is unclear how these functions are performed. Here, we ask whether a subpopulation of zebrafish pineal cells, which express glial markers and visual cycle genes, is involved in maintaining photoreceptors. Selective ablation of these cells leads to a loss of pineal photoreceptors. Moreover, these cells internalize exorhodopsin that is secreted by pineal rod-like photoreceptors, and in turn release CD63-positive extracellular vesicles (EVs) that are taken up by pdgfrb-positive phagocytic cells in the forebrain meninges. These results identify a subpopulation of glial cells that is critical for pineal photoreceptor survival and indicate the existence of cells in the forebrain meninges that receive EVs released by these pineal cells and potentially function in waste disposal.

The circadian clock, which drives a wide range of bodily rhythms in synchrony with the day–night cycle, is based on a molecular oscillator that ticks with a period of approximately 24 h. Timed proteasomal degradation of clock components is central to the fine-tuning of the oscillator’s period. FBXL3 is a protein that functions as a substrate-recognition factor in the E3 ubiquitin ligase complex, and was originally shown in mice to mediate degradation of CRY proteins and thus contribute to the mammalian circadian clock mechanism. By exome sequencing, we have identified a FBXL3 mutation in patients with syndromic developmental delay accompanied by morphological abnormalities and intellectual disability, albeit with a normal sleep pattern. We have investigated the function of FBXL3 in the zebrafish, an excellent model to study both vertebrate development and circadian clock function and, like humans, a diurnal species. Loss of fbxl3a function in zebrafish led to disruption of circadian rhythms of promoter activity and mRNA expression as well as locomotor activity and sleep–wake cycles. However, unlike humans, no morphological effects were evident. These findings point to an evolutionary conserved role for FBXL3 in the circadian clock system across vertebrates and to the acquisition of developmental roles in humans.

The zebrafish represents a powerful model for exploring how light regulates the circadian clock due to the direct light sensitivity of its peripheral clocks, a property that is retained even in organ cultures as well as zebrafish-derived cell lines. Light-inducible expression of the per2 clock gene has been predicted to play a vital function in relaying light information to the core circadian clock mechanism in many organisms, including zebrafish. To directly test the contribution of per2 to circadian clock function in zebrafish, we have generated a loss-of-function per2 gene mutation. Our results reveal a tissue-specific role for the per2 gene in maintaining rhythmic expression of circadian clock genes, as well as clock-controlled genes, and an impact on the rhythmic behavior of intact zebrafish larvae. Furthermore, we demonstrate that disruption of the per2 gene impacts on the circadian regulation of the cell cycle in vivo. Based on these results, we hypothesize that in addition to serving as a central element of the light input pathway to the circadian clock, per2 acts as circadian regulator of tissue-specific physiological functions in zebrafish.