MicroRNA classification and discovery for major depressive disorder diagnosis: Towards a robust and interpretable machine learning approach

BACKGROUND

Major depressive disorder (MDD) is notably underdiagnosed and undertreated due to its complex nature and subjective diagnostic methods. Biomarker identification would help provide a clearer understanding of MDD aetiology. Although machine learning (ML) has been implemented in previous studies to study the alteration of microRNA (miRNA) levels in MDD cases, clinical translation has not been feasible due to the lack of interpretability (i.e. too many miRNAs for consideration) and stability.

METHODS

This study applied logistic regression (LR) model to the blood miRNA expression profile to differentiate patients with MDD (n = 60) from healthy controls (HCs, n = 60). Embedded (L1-regularised logistic regression) feature selector was utilised to extract clinically relevant miRNAs, and optimized for clinical application.

RESULTS

Patients with MDD could be differentiated from HCs with the area under the receiver operating characteristic curve (AUC) of 0.81 on testing data when all available miRNAs were considered (which served as a benchmark). Our LR model selected miRNAs up to 5 (known as LR-5 model) emerged as the best model because it achieved a moderate classification ability (AUC = 0.75), relatively high interpretability (feature number = 5) and stability (ϕ̂Z=0.55) compared to the benchmark. The top-ranking miRNAs identified by our model have demonstrated associations with MDD pathways involving cytokine signalling in the immune system, the reelin signalling pathway, programmed cell death and cellular responses to stress.

CONCLUSION

The LR-5 model, which is optimised based on ML design factors, may lead to a robust and clinically usable MDD diagnostic tool.

Loss of Ninjurin1 alleviates acetaminophen-induced liver injury via enhancing AMPKα-NRF2 pathway

Acetaminophen (APAP), a widely used pain and fever reliever, is a major contributor to drug-induced liver injury, as its toxic metabolites such as NAPQI induce oxidative stress and hepatic necrosis. While N-acetylcysteine serves as the primary treatment for APAP-induced liver injury (AILI), its efficacy is confined to a narrow window of 8-24 h post-APAP overdose. Beyond this window, liver transplantation emerges as the final recourse, prompting ongoing research to pinpoint novel therapeutic targets aimed at enhancing AILI treatment outcomes. Nerve injury-induced protein 1 (Ninjurin1; Ninj1), initially recognized as an adhesion molecule, has been implicated in liver damage stemming from factors like TNFα and ischemia-reperfusion. Nonetheless, its role in oxidative stress-related liver diseases, including AILI, remains unexplored. In this study, we observed up-regulation of Ninj1 expression in the livers of both human DILI patients and the AILI mouse model. Through the utilization of Ninj1 null mice, hepatocyte-specific Ninj1 KO mice, and myeloid-specific Ninj1 KO mice, we unveiled that the loss of Ninj1 in hepatocytes, rather than myeloid cells, exerts alleviative effects on AILI irrespective of sex dependency. Further in vitro experiments demonstrated that Ninj1 deficiency shields hepatocytes from APAP-induced oxidative stress, mitochondrial dysfunctions, and cell death by bolstering NRF2 stability via activation of AMPKα. In summary, our findings imply that Ninj1 likely plays a role in AILI, and its deficiency confers protection against APAP-induced hepatotoxicity through the AMPKα-NRF2 pathway.

Neuroligin1 in excitatory synapses contributes to long-term cognitive impairments after repeated neonatal sevoflurane exposures

BACKGROUND

Repeated sevoflurane exposures in neonatal rats may lead to neuronal apoptosis affecting long-term cognitive function, the mechanism is unknown. Neuroligin1 (NL1) is essential for normal excitatory transmission and long-term synaptic plasticity in the hippocampus of intact animals. Herein, we explore the role of NL1 in hippocampal excitatory synapses on long-term cognitive impairments induced by repeated sevoflurane exposures in neonatal rats.

METHODS

From postnatal day six (P6) to P8, neonatal rats were exposed to 30% oxygen or 3% sevoflurane +30% oxygen for 2 h daily. Rats from each litter were randomly assigned to five groups: control group (Con), native control adeno-associated virus (NC-AAV) group (Con + NC-AAV), sevoflurane group (Sev), sevoflurane + recombinant RNAi adeno-associated virus targeting NL1 downregulation (NL1--AAV) group (Sev + NL1--AAV) and control + recombinant RNAi adeno-associated virus targeting NL1 upregulation (NL1+-AAV) group (Con + NL1+-AAV). Animals were injected with NC-AAV or NL1-AAV into the bilateral hippocampal CA1 area and caged on P21. From P35 to P40, behavioral tests including open field (OF), novel object recognition (NOR), and fear conditioning (FC) tests were performed to assess cognitive function in adolescent rats. In another experiment, rat brains were harvested for immunofluorescence staining, western blotting, co-immunoprecipitation, and real-time polymerase chain reaction (PCR).

RESULTS

We found that the mRNA and protein levels of NL1 were substantially higher in the Sev group than in the Con group. Immunofluorescence showed that NL1 and PSD95 were highly colocalized in hippocampal CA1 area and vesicular GABA transporter (vGAT) around neurons decreased after repeated sevoflurane exposures. Co-immunoprecipitation showed that the amount of PSD95 with NL1 antibody was significantly increased in the Sev group compared to the Con group. These rats had a poorer performance in the NOR and FC tests than control rats when they were adolescents. These results were reversed by NL1--AAV injection into the CA1 area. NL1+-AAV group was similar to the Sev group.

CONCLUSION

We have demonstrated that repeated neonatal sevoflurane exposures decreased inhibitory synaptic inputs (labelled by vGAT) around neurons, which may influence the upregulation of NL1 in hippocampal excitatory synapses and enhanced NL1/PSD95 interaction, ultimately leading to long-term cognitive impairments in adolescent rats. Injecting NL1--AAV reversed this damage. These results suggested that NL1 in excitatory synapses contributes to long-term cognitive impairments after repeated neonatal sevoflurane exposures.

HLA-DQB1*05 subtypes and not DRB1*10:01 mediates risk in anti-IgLON5 disease

Anti-IgLON5 disease is a rare and likely underdiagnosed subtype of autoimmune encephalitis. The disease displays a heterogeneous phenotype that includes sleep, movement and bulbar-associated dysfunction. The presence of IgLON5-antibodies in CSF/serum, together with a strong association with HLA-DRB1*10:01∼DQB1*05:01, supports an autoimmune basis. In this study, a multicentric human leukocyte antigen (HLA) study of 87 anti-IgLON5 patients revealed a stronger association with HLA-DQ than HLA-DR. Specifically, we identified a predisposing rank-wise association with HLA-DQA1*01:05∼DQB1*05:01, HLA-DQA1*01:01∼DQB1*05:01 and HLA-DQA1*01:04∼DQB1*05:03 in 85% of patients. HLA sequences and binding cores for these three DQ heterodimers were similar, unlike those of linked DRB1 alleles, supporting a causal link to HLA-DQ. This association was further reflected in an increasingly later age of onset across each genotype group, with a delay of up to 11 years, while HLA-DQ-dosage dependent effects were also suggested by reduced risk in the presence of non-predisposing DQ1 alleles. The functional relevance of the observed HLA-DQ molecules was studied with competition binding assays. These proof-of-concept experiments revealed preferential binding of IgLON5 in a post-translationally modified, but not native, state to all three risk-associated HLA-DQ receptors. Further, a deamidated peptide from the Ig2-domain of IgLON5 activated T cells in two patients, compared with one control carrying HLA-DQA1*01:05∼DQB1*05:01. Taken together, these data support a HLA-DQ-mediated T-cell response to IgLON5 as a potentially key step in the initiation of autoimmunity in this disease.

Rare heterozygous genetic variants of NRXN and NLGN gene families involved in synaptic function and their association with neurodevelopmental disorders

The interaction of neurexins (NRXNs) in the presynaptic membrane with postsynaptic cell adhesion molecules called neuroligins (NLGNs) is critical for this synaptic function. Impaired synaptic functions are emphasized in neurodevelopmental disorders to uncover etiological factors. We evaluated variants in NRXN and NLGN genes encoding molecules located directly at the synapse in patients with neuropsychiatric disorders using clinical exome sequencing and chromosomal microarray. We presented detailed clinical findings of cases carrying heterozygous NRXN1 (c.190C > T, c.1679C > T and two copy number variations [CNVs]), NRXN2 (c.808dup, c.1901G > T), NRXN3 (c.3889C > T), and NLGN1 (c.269C > G, c.473T > A) gene variants. In addition, three novel variants were identified in the NRXN1 (c.1679C > T), NRXN3 [c.3889C > T (p.Pro1297Ser)], and NLGN1 [c.473T > A (p.Ile158Lys)] genes. We emphasize the clinical findings of CNVs of the NRXN1 gene causing a more severe clinical presentation than single nucleotide variants of the NRXN1 gene in this study. We detected an NRXN2 gene variant (c.808dup) with low allelic frequency in two unrelated cases with the same diagnosis. We emphasize the importance of this variant for future studies. We suggest that NRXN2, NRXN3, and NLGN1 genes, which are less frequently reported than NRXN1 gene variants, may also be associated with neurodevelopmental disorders.

Reelin differentially shapes dendrite morphology of medial entorhinal cortical ocean and island cells

The function of medial entorhinal cortex layer II (MECII) excitatory neurons has been recently explored. MECII dysfunction underlies deficits in spatial navigation and working memory. MECII neurons comprise two major excitatory neuronal populations, pyramidal island and stellate ocean cells, in addition to the inhibitory interneurons. Ocean cells express reelin and surround clusters of island cells that lack reelin expression. The influence of reelin expression by ocean cells and interneurons on their own morphological differentiation and that of MECII island cells has remained unknown. To address this, we used a conditional reelin knockout (RelncKO) mouse to induce reelin deficiency postnatally in vitro and in vivo. Reelin deficiency caused dendritic hypertrophy of ocean cells, interneurons and only proximal dendritic compartments of island cells. Ca2+ recording showed that both cell types exhibited an elevation of calcium frequencies in RelncKO, indicating that the hypertrophic effect is related to excessive Ca2+ signalling. Moreover, pharmacological receptor blockade in RelncKO mouse revealed malfunctioning of GABAB, NMDA and AMPA receptors. Collectively, this study emphasizes the significance of reelin in neuronal growth, and its absence results in dendrite hypertrophy of MECII neurons.

Reelin links Apolipoprotein E4, Tau, and Amyloid-β in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder that affects the cerebral cortex and hippocampus, and is characterised by progressive cognitive decline and memory loss. A recent report of a patient carrying a novel gain-of-function variant of RELN (H3447R, termed RELN-COLBOS) who developed resilience against presenilin-linked autosomal-dominant AD (ADAD) has generated enormous interest. The RELN-COLBOS variant enhances interactions with the apolipoprotein E receptor 2 (ApoER2) and very-low-density lipoprotein receptor (VLDLR), which are associated with delayed AD onset and progression. These findings were validated in a transgenic mouse model. Reelin is involved in neurodevelopment, neurogenesis, and neuronal plasticity. The evidence accumulated thus far has demonstrated that the Reelin pathway links apolipoprotein E4 (ApoE4), amyloid-β (Aβ), and tubulin-associated unit (Tau), which are key proteins that have been implicated in AD pathogenesis. Reelin and key components of the Reelin pathway have been highlighted as potential therapeutic targets and biomarkers for AD.

Neuroligins facilitate the development of bone cancer pain via regulating synaptic transmission: an experimental study

BACKGROUND

The underlying mechanism of chronic pain involves the plasticity in synaptic receptors and neurotransmitters. This study aimed to investigate potential roles of Neuroligins (NLs) within the spinal dorsal horn of rats in a newly established Bone Cancer Pain (BCP) model. The objective was to explore the mechanism of neuroligin involved in the occurrence and development of bone cancer pain.

METHODS

Using our rat BCP model, we assessed pain hypersensitivity over time. Quantitative real-time polymerase chain reaction and Western blot analysis were performed to investigate NL expression, and NLs were overexpressed in the rat spinal cord using lentiviral vectors. Immunofluorescence staining and whole-cell patch-clamp recordings were deployed to investigate the role of NLs in the development of BCP.

RESULTS

We observed reduced expression levels of NL1 and NL2, but not of NL3, within the rat spinal cord, which were found to be associated with and essential for the development of BCP in our model. Accordingly, NL1 or NL2 overexpression in the spinal cord alleviated mechanical hypersensitivity of rats. Electrophysiological experiments indicated that NL1 and NL2 are involved in BCP via regulating γ-aminobutyric acid-ergic interneuronal synapses and the activity of glutamatergic interneuronal synapses, respectively.

CONCLUSIONS

Our observations unravel the role of NLs in cancer-related chronic pain and further suggest that inhibitory mechanisms are central features of BCP in the spinal dorsal horn. These results provide a new perspective and basis for subsequent studies elucidating the onset and progression of BCP.

MDGAs perform activity-dependent synapse type-specific suppression via distinct extracellular mechanisms

MDGA (MAM domain containing glycosylphosphatidylinositol anchor) family proteins were previously identified as synaptic suppressive factors. However, various genetic manipulations have yielded often irreconcilable results, precluding precise evaluation of MDGA functions. Here, we found that, in cultured hippocampal neurons, conditional deletion of MDGA1 and MDGA2 causes specific alterations in synapse numbers, basal synaptic transmission, and synaptic strength at GABAergic and glutamatergic synapses, respectively. Moreover, MDGA2 deletion enhanced both N-methyl-D-aspartate (NMDA) receptor- and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated postsynaptic responses. Strikingly, ablation of both MDGA1 and MDGA2 abolished the effect of deleting individual MDGAs that is abrogated by chronic blockade of synaptic activity. Molecular replacement experiments further showed that MDGA1 requires the meprin/A5 protein/PTPmu (MAM) domain, whereas MDGA2 acts via neuroligin-dependent and/or MAM domain-dependent pathways to regulate distinct postsynaptic properties. Together, our data demonstrate that MDGA paralogs act as unique negative regulators of activity-dependent postsynaptic organization at distinct synapse types, and cooperatively contribute to adjustment of excitation-inhibition balance.

ALCAM-mediated cDC1 CD8 T cells interactions are suppressed in advanced lung tumors

Conventional type 1 dendritic cells (cDC1) are critical regulators of anti-tumoral T-cell responses. The structure and abundance of intercellular contacts between cDC1 and CD8 T cells in cancer tissues is important to determine the outcome of the T-cell response. However, the molecular determinants controlling the stability of cDC1-CD8 interactions during cancer progression remain poorly investigated. Here, we generated a genetic model of non-small cell lung cancer crossed to a fluorescent cDC1 reporter (KP-XCR1venus) to allow the detection of cDC1-CD8T cell clusters in tumor tissues across tumor stages. We found that cDC1-CD8 clusters are abundant and productive at the early stages of tumor development but progressively diminish in advanced tumors. Transcriptional profiling and flow cytometry identified the adhesion molecule ALCAM/CD166 (Activated Leukocyte Cell Adhesion Molecule, ligand of CD6) as highly expressed by lung cDC1 and significantly downregulated in advanced tumors. Analysis of human datasets indicated that ALCAM is downregulated in non-small cell lung cancer and its expression correlates to better prognosis. Mechanistically, triggering ALCAM on lung cDC1 induces cytoskeletal remodeling and contact formation whereas its blockade prevents T-cell activation. Together, our results indicate that ALCAM is important to stabilize cDC1-CD8 interactions at early tumor stages, while its loss in advanced tumors contributes to immune evasion.

Neurexins control the strength and precise timing of glycinergic inhibition in the auditory brainstem

Neurexins play diverse functions as presynaptic organizers in various glutamatergic and GABAergic synapses. However, it remains unknown whether and how neurexins are involved in shaping functional properties of the glycinergic synapses, which mediate prominent inhibition in the brainstem and spinal cord. To address these issues, we examined the role of neurexins in a model glycinergic synapse between the principal neuron in the medial nucleus of the trapezoid body (MNTB) and the principal neuron in the lateral superior olive (LSO) in the auditory brainstem. Combining RNAscope with stereotactic injection of AAV-Cre in the MNTB of neurexin1/2/3 conditional triple knockout mice, we showed that MNTB neurons highly express all isoforms of neurexins although their expression levels vary remarkably. Selective ablation of all neurexins in MNTB neurons not only reduced the amplitude but also altered the kinetics of the glycinergic synaptic transmission at LSO neurons. The synaptic dysfunctions primarily resulted from an impaired Ca2+ sensitivity of release and a loosened coupling between voltage-gated Ca2+ channels and synaptic vesicles. Together, our current findings demonstrate that neurexins are essential in controlling the strength and temporal precision of the glycinergic synapse, which therefore corroborates the role of neurexins as key presynaptic organizers in all major types of fast chemical synapses.

Exome sequencing in four families with neurodevelopmental disorders: genotype-phenotype correlation and identification of novel disease-causing variants in VPS13B and RELN

Neurodevelopmental disorders (NDDs) are a clinically and genetically heterogeneous group of early-onset pediatric disorders that affect the structure and/or function of the central or peripheral nervous system. Achieving a precise molecular diagnosis for NDDs may be challenging due to the diverse genetic underpinnings and clinical variability. In the current study, we investigated the underlying genetic cause(s) of NDDs in four unrelated Pakistani families. Using exome sequencing (ES) as a diagnostic approach, we identified disease-causing variants in established NDD-associated genes in all families, including one hitherto unreported variant in RELN and three recurrent variants in VPS13B, DEGS1, and SPG11. Overall, our study highlights the potential of ES as a tool for clinical diagnosis.

Reelin Regulates Developmental Desynchronization Transition of Neocortical Network Activity

During the first and second stages of postnatal development, neocortical neurons exhibit a wide range of spontaneous synchronous activity (SSA). Towards the end of the second postnatal week, the SSA is replaced by a more sparse and desynchronized firing pattern. The developmental desynchronization of neocortical spontaneous neuronal activity is thought to be intrinsically generated, since sensory deprivation from the periphery does not affect the time course of this transition. The extracellular protein reelin controls various aspects of neuronal development through multimodular signaling. However, so far it is unclear whether reelin contributes to the developmental desynchronization transition of neocortical neurons. The present study aims to investigate the role of reelin in postnatal cortical developmental desynchronization using a conditional reelin knockout (RelncKO) mouse model. Conditional reelin deficiency was induced during early postnatal development, and Ca2+ recordings were conducted from organotypic cultures (OTCs) of the somatosensory cortex. Our results show that both wild type (wt) and RelncKO exhibited an SSA pattern during the early postnatal week. However, at the end of the second postnatal week, wt OTCs underwent a transition to a desynchronized network activity pattern, while RelncKO activity remained synchronous. This changing activity pattern suggests that reelin is involved in regulating the developmental desynchronization of cortical neuronal network activity. Moreover, the developmental desynchronization impairment observed in RelncKO was rescued when RelncKO OTCs were co-cultured with wt OTCs. Finally, we show that the developmental transition to a desynchronized state at the end of the second postnatal week is not dependent on glutamatergic signaling. Instead, the transition is dependent on GABAAR and GABABR signaling. The results suggest that reelin controls developmental desynchronization through GABAAR and GABABR signaling.

Fas2EB112: a tale of two chromosomes

The cell-cell adhesion molecule Fasciclin II (Fas2) has long been studied for its evolutionarily conserved role in axon guidance. It is also expressed in the follicular epithelium, where together with a similar protein, Neuroglian (Nrg), it helps to drive the reintegration of cells born out of the tissue plane. Remarkably, one Fas2 protein null allele, Fas2G0336, demonstrates a mild reintegration phenotype, whereas work with the classic null allele Fas2EB112 showed more severe epithelial disorganization. These observations raise the question of which allele (if either) causes a bona fide loss of Fas2 protein function. The problem is not only relevant to reintegration but fundamentally important to understanding what this protein does and how it works: Fas2EB112 has been used in at least 37 research articles, and Fas2G0336 in at least three. An obvious solution is that one of the two chromosomes carries a modifier that either suppresses (Fas2G0336) or enhances (Fas2EB112) phenotypic severity. We find not only the latter to be the case, but identify the enhancing mutation as Nrg14, also a classic null allele.

Conditional deletion of neurexin-2 impaired behavioral flexibility to alterations in action-outcome contingency

Neurexins (Nrxns) are critical for synapse organization and their mutations have been documented in autism spectrum disorder, schizophrenia, and epilepsy. We recently reported that conditional deletion of Nrxn2, under the control of Emx1Cre promoter, predominately expressed in the neocortex and hippocampus (Emx1-Nrxn2 cKO mice) induced stereotyped patterns of behavior in mice, suggesting behavioral inflexibility. In this study, we investigated the effects of Nrxn2 deletion through two different conditional approaches targeting presynaptic cortical neurons projecting to dorsomedial striatum on the flexibility between goal-directed and habitual actions in response to devaluation of action-outcome (A-O) contingencies in an instrumental learning paradigm or upon reversal of A-O contingencies in a water T-maze paradigm. Nrxn2 deletion through both the conditional approaches induced an inability of mice to discriminate between goal-directed and habitual action strategies in their response to devaluation of A-O contingency. Emx1-Nrxn2 cKO mice exhibited reversal learning deficits, indicating their inability to adopt new action strategies. Overall, our studies showed that Nrxn2 deletion through two distinct conditional deletion approaches impaired flexibility in response to alterations in A-O contingencies. These investigations can lay the foundation for identification of novel genetic factors underlying behavioral inflexibility.

Interdependency of NINJ2 gene expression and polymorphism with susceptibility and response to interferon beta in patients with multiple sclerosis

OBJECTIVE

Multiple sclerosis (MS) is a multifactorial inflammatory and autoimmune condition that lead to chronic neurodegeneration and central nervous system (CNS) demyelination that mainly affects young adults. The incidence and prevalence rate of MS considerably vary in ethnicities and geographic regions and affecting women more than men. Interferon-β (IFN-β) is the first-line disease management for MS, while the majority of affected members does not respond to the IFN-β. Numerous recent studies shown a significant relationship between genetic variations and responsiveness to the IFN-β. Therefore, determining the genetic differences in the drug response could help determine precise treatment strategies.

METHODS

The genotyping of the rs7298096 polymorphism (SNP) and NINJ2 gene expression were assessed in 99 responders and 106 non-responder patients with IFN-β treated RRMS.

RESULTS

The distribution of rs7298096 SNP was significantly different in the responders and non-responder patients and the NINJ2 gene expression considerably increased in the non-responder patients compare to the responders. The NINJ2 gene expression level in the AA genotype of the non-responder group was higher than to the other genotypes of both groups.

CONCLUSION

Our results showed that the NINJ2 gene expression level and rs7298096 genotype possibly affect the response to the IFN-β in patients with RRMS.

Differential contribution of canonical and noncanonical NLGN3 pathways to early social development and memory performance

Neuroligin (NLGN) 3 is a postsynaptic cell adhesion protein organizing synapse formation through two different types of transsynaptic interactions, canonical interaction with neurexins (NRXNs) and a recently identified noncanonical interaction with protein tyrosine phosphatase (PTP) δ. Although, NLGN3 gene is known as a risk gene for neurodevelopmental disorders such as autism spectrum disorder (ASD) and intellectual disability (ID), the pathogenic contribution of the canonical NLGN3-NRXN and noncanonical NLGN3-PTPδ pathways to these disorders remains elusive. In this study, we utilized Nlgn3 mutant mice selectively lacking the interaction with either NRXNs or PTPδ and investigated their social and memory performance. Neither Nlgn3 mutants showed any social cognitive deficiency in the social novelty recognition test. However, the Nlgn3 mutant mice lacking the PTPδ pathway exhibited significant decline in the social conditioned place preference (sCPP) at the juvenile stage, suggesting the involvement of the NLGN3-PTPδ pathway in the regulation of social motivation and reward. In terms of learning and memory, disrupting the canonical NRXN pathway attenuated contextual fear conditioning while disrupting the noncanonical NLGN3-PTPδ pathway enhanced it. Furthermore, disruption of the NLGN3-PTPδ pathway negatively affected the remote spatial reference memory in the Barnes maze test. These findings highlight the differential contributions of the canonical NLGN3-NRXN and noncanonical NLGN3-PTPδ synaptogenic pathways to the regulation of higher order brain functions associated with ASD and ID.

Effects of Ninjurin 2 polymorphisms on susceptibility to coronary heart disease

OBJECTIVE

The aim of this study was to explore the effects of Ninjurin 2 (NINJ2) polymorphisms on susceptibility to coronary heart disease (CHD).

METHODS

We conducted a case-control study with 499 CHD cases and 505 age and gender-matched controls. Five single nucleotide polymorphisms (SNPs) in NINJ2 (rs118050317, rs75750647, rs7307242, rs10849390, and rs11610368) were genotyped by the Agena MassARRAY platform. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression analysis to assess the association of NINJ2 polymorphisms and CHD risk-adjusted for age and gender. What's more, risk genes and molecular functions were screened via protein-protein interaction (PPI) network and functional enrichment analysis.

RESULTS

Rs118050317 in NINJ2 significantly increased CHD risk in people aged more than 60 years and women. Rs118050317 and rs7307242 had strong relationships with hypertension risk in CHD patients. Additionally, rs75750647 exceedingly raised diabetes risk in cases under multiple models, whereas rs10849390 could protect CHD patients from diabetes in allele, homozygote, and additive models. We also observed two blocks in NINJ2. Further interaction network and enrichment analysis showed that NINJ2 played a greater role in the pathogenesis and progression of CHD.

CONCLUSION

Our results suggest that NINJ2 polymorphisms are associated with CHD risk.

ApoER2-Dab1 disruption as the origin of pTau-associated neurodegeneration in sporadic Alzheimer's disease

In sporadic Alzheimer's disease (sAD) specific regions, layers and neurons accumulate hyperphosphorylated Tau (pTau) and degenerate early while others remain unaffected even in advanced disease. ApoER2-Dab1 signaling suppresses Tau phosphorylation as part of a four-arm pathway that regulates lipoprotein internalization and the integrity of actin, microtubules, and synapses; however, the role of this pathway in sAD pathogenesis is not fully understood. We previously showed that multiple ApoER2-Dab1 pathway components including ApoE, Reelin, ApoER2, Dab1, pP85αTyr607, pLIMK1Thr508, pTauSer202/Thr205 and pPSD95Thr19 accumulate together within entorhinal-hippocampal terminal zones in sAD, and proposed a unifying hypothesis wherein disruption of this pathway underlies multiple aspects of sAD pathogenesis. However, it is not yet known whether ApoER2-Dab1 disruption can help explain the origin(s) and early progression of pTau pathology in sAD. In the present study, we applied in situ hybridization and immunohistochemistry (IHC) to characterize ApoER2 expression and accumulation of ApoER2-Dab1 pathway components in five regions known to develop early pTau pathology in 64 rapidly autopsied cases spanning the clinicopathological spectrum of sAD. We found that (1) these selectively vulnerable neuron populations strongly express ApoER2; and (2) multiple ApoER2-Dab1 components representing all four arms of this pathway accumulate in abnormal neurons and neuritic plaques in mild cognitive impairment (MCI) and sAD cases and correlate with histological progression and cognitive deficits. Multiplex-IHC revealed that Dab1, pP85αTyr607, pLIMK1Thr508, pTauSer202/Thr205 and pPSD95Thr19 accumulate together within many of the same ApoER2-expressing neurons and in the immediate vicinity of ApoE/ApoJ-enriched extracellular plaques. Collective findings reveal that pTau is only one of many ApoER2-Dab1 pathway components that accumulate in multiple neuroanatomical sites in the earliest stages of sAD and provide support for the concept that ApoER2-Dab1 disruption drives pTau-associated neurodegeneration in human sAD.

Associative memory neurons of encoding multi-modal signals are recruited by neuroligin-3-mediated new synapse formation

The joint storage and reciprocal retrieval of learnt associated signals are presumably encoded by associative memory cells. In the accumulation and enrichment of memory contents in lifespan, a signal often becomes a core signal associatively shared for other signals. One specific group of associative memory neurons that encode this core signal likely interconnects multiple groups of associative memory neurons that encode these other signals for their joint storage and reciprocal retrieval. We have examined this hypothesis in a mouse model of associative learning by pairing the whisker tactile signal sequentially with the olfactory signal, the gustatory signal, and the tail-heating signal. Mice experienced this associative learning show the whisker fluctuation induced by olfactory, gustatory, and tail-heating signals, or the other way around, that is, memories to multi-modal associated signals featured by their reciprocal retrievals. Barrel cortical neurons in these mice become able to encode olfactory, gustatory, and tail-heating signals alongside the whisker signal. Barrel cortical neurons interconnect piriform, S1-Tr, and gustatory cortical neurons. With the barrel cortex as the hub, the indirect activation occurs among piriform, gustatory, and S1-Tr cortices for the second-order associative memory. These associative memory neurons recruited to encode multi-modal signals in the barrel cortex for associative memory are downregulated by neuroligin-3 knockdown. Thus, associative memory neurons can be recruited as the core cellular substrate to memorize multiple associated signals for the first-order and the second-order of associative memories by neuroligin-3-mediated synapse formation, which constitutes neuronal substrates of cognitive activities in the field of memoriology.

Distinct neurexin isoforms cooperate to initiate and maintain foraging activity

Neurexins are synaptic adhesion molecules that play diverse roles in synaptic development, function, maintenance, and plasticity. Neurexin genes have been associated with changes in human behavior, where variants in NRXN1 are associated with autism, schizophrenia, and Tourette syndrome. While NRXN1, NRXN2, and NRXN3 all encode major α and β isoforms, NRXN1 uniquely encodes a γ isoform, for which mechanistic roles in behavior have yet to be defined. Here, we show that both α and γ isoforms of neurexin/nrx-1 are required for the C. elegans behavioral response to food deprivation, a sustained period of hyperactivity upon food loss. We find that the γ isoform regulates initiation and the α isoform regulates maintenance of the behavioral response to food deprivation, demonstrating cooperative function of multiple nrx-1 isoforms in regulating a sustained behavior. The γ isoform alters monoamine signaling via octopamine, relies on specific expression of NRX-1 isoforms throughout the relevant circuit, and is independent of neuroligin/nlg-1, the canonical trans-synaptic partner of nrx-1. The α isoform regulates the pre-synaptic structure of the octopamine producing RIC neuron and its maintenance role is conditional on neuroligin/nlg-1. Collectively, these results demonstrate that neurexin isoforms can have separate behavioral roles and act cooperatively across neuronal circuits to modify behavior, highlighting the need to directly analyze and consider all isoforms when defining the contribution of neurexins to behavior.

Liver sinusoidal endothelial cells show reduced scavenger function and downregulation of Fc gamma receptor IIb, yet maintain a preserved fenestration in the Glmpgt/gt mouse model of slowly progressing liver fibrosis

Liver sinusoidal endothelial cells (LSECs) are fenestrated endothelial cells with a unique, high endocytic clearance capacity for blood-borne waste macromolecules and colloids. This LSEC scavenger function has been insufficiently characterized in liver disease. The Glmpgt/gt mouse lacks expression of a subunit of the MFSD1/GLMP lysosomal membrane protein transporter complex, is born normal, but soon develops chronic, mild hepatocyte injury, leading to slowly progressing periportal liver fibrosis, and splenomegaly. This study examined how LSEC scavenger function and morphology are affected in the Glmpgt/gt model. FITC-labelled formaldehyde-treated serum albumin (FITC-FSA), a model ligand for LSEC scavenger receptors was administered intravenously into Glmpgt/gt mice, aged 4 months (peak of liver inflammation), 9-10 month, and age-matched Glmpwt/wt mice. Organs were harvested for light and electron microscopy, quantitative image analysis of ligand uptake, collagen accumulation, LSEC ultrastructure, and endocytosis receptor expression (also examined by qPCR and western blot). In both age groups, the Glmpgt/gt mice showed multifocal liver injury and fibrosis. The uptake of FITC-FSA in LSECs was significantly reduced in Glmpgt/gt compared to wild-type mice. Expression of LSEC receptors stabilin-1 (Stab1), and mannose receptor (Mcr1) was almost similar in liver of Glmpgt/gt mice and age-matched controls. At the same time, immunostaining revealed differences in the stabilin-1 expression pattern in sinusoids and accumulation of stabilin-1-positive macrophages in Glmpgt/gt liver. FcγRIIb (Fcgr2b), which mediates LSEC endocytosis of soluble immune complexes was widely and significantly downregulated in Glmpgt/gt liver. Despite increased collagen in space of Disse, LSECs of Glmpgt/gt mice showed well-preserved fenestrae organized in sieve plates but the frequency of holes >400 nm in diameter was increased, especially in areas with hepatocyte damage. In both genotypes, FITC-FSA also distributed to endothelial cells of spleen and bone marrow sinusoids, suggesting that these locations may function as possible compensatory sites of clearance of blood-borne scavenger receptor ligands in liver fibrosis.

Mouse models of human CNTNAP1-associated congenital hypomyelinating neuropathy and genetic restoration of murine neurological deficits

The Contactin-associated protein 1 (Cntnap1) mouse mutants fail to establish proper axonal domains in myelinated axons. Human CNTNAP1 mutations are linked to hypomyelinating neuropathy-3, which causes severe neurological deficits. To understand the human neuropathology and to model human CNTNAP1C323R and CNTNAP1R764C mutations, we generated Cntnap1C324R and Cntnap1R765C mouse mutants, respectively. Both Cntnap1 mutants show weight loss, reduced nerve conduction, and progressive motor dysfunction. The paranodal ultrastructure shows everted myelin loops and the absence of axo-glial junctions. Biochemical analysis reveals that these Cntnap1 mutant proteins are nearly undetectable in the paranodes, have reduced surface expression and stability, and are retained in the neuronal soma. Postnatal transgenic expression of Cntnap1 in the mutant backgrounds rescues the phenotypes and restores the organization of axonal domains with improved motor function. This study uncovers the mechanistic impact of two human CNTNAP1 mutations in a mouse model and provides proof of concept for gene therapy for CNTNAP1 patients.

Co-cultures of cerebellar slices from mice with different reelin genetic backgrounds as a model to study cortical lamination

Background: Reelin has fundamental functions in the developing and mature brain. Its absence gives rise to the Reeler phenotype in mice, the first described cerebellar mutation. In homozygous mutants missing the Reelin gene ( reln -/-), neurons are incapable of correctly positioning themselves in layered brain areas such as the cerebral and cerebellar cortices. We here demonstrate that by employing ex vivo cultured cerebellar slices one can reduce the number of animals and use a non-recovery procedure to analyze the effects of Reelin on the migration of Purkinje neurons (PNs). Methods: We generated mouse hybrids (L7-GFP relnF1/) with green fluorescent protein (GFP)-tagged PNs, directly visible under fluorescence microscopy. We then cultured the slices obtained from mice with different reln genotypes and demonstrated that when the slices from reln -/- mutants were co-cultured with those from reln +/- mice, the Reelin produced by the latter induced migration of the PNs to partially rescue the normal layered cortical histology. We have confirmed this observation with Voronoi tessellation to analyze PN dispersion. Results: In images of the co-cultured slices from reln -/- mice, Voronoi polygons were larger than in single-cultured slices of the same genetic background but smaller than those generated from slices of reln +/- animals. The mean roundness factor, area disorder, and roundness factor homogeneity were different when slices from reln -/- mice were cultivated singularly or co-cultivated, supporting mathematically the transition from the clustered organization of the PNs in the absence of Reelin to a layered structure when the protein is supplied ex vivo. Conclusions: Neurobiologists are the primary target users of this 3Rs approach. They should adopt it for the possibility to study and manipulate ex vivo the activity of a brain-secreted or genetically engineered protein (scientific perspective), the potential reduction (up to 20%) of the animals used, and the total avoidance of severe surgery (3Rs perspective).