Functions and the related signaling pathways of the neurotrophic factor neuritin

Neurotrophic factor neuritin ameliorates streptozotocin-induced Alzheimer's disease-like impairment of memory, neuroinflammation, apoptotic factors and compensates hippocampal neuritin expression

Alzheimer's disease (AD) is the main cause of dementia in the elderly, and is becoming one of the most expensive and deadly diseases. Deficiency of neurotrophic factors signaling is an important cause of this disease. Therefore, we investigated whether neuritin as a neurotrophic factor can have a neuroprotective effect against streptozotocin (STZ)-induced rat model of AD. The animals were bilaterally injected with intra hippocampal-STZ (3 mg/kg). Different concentrations of neuritin (0.5, 1, 1.5 µg/rat) were administrated 15 min before STZ injection. After 14 days, the rats were evaluated for cognitive performance using novel object recognition (NOR), open field and Morris water maze (MWM) tests and then sacrificed for biochemical analysis (by real-time PCR and western blot examinations). The results demonstrated that the STZ- induced learning and memory impairments were significantly prevented by 1.5 µg neuritin. Moreover, the increased levels of inflammatory factors (NF-κb, TNF-α and IL-1β) and apoptotic parameters (cytochrome c and caspase‑3) in STZ- treated rats were also significantly decreased by neuritin. In addition, hippocampal neuritin gene expression was downregulated by STZ injection, which was reversed by intra hippocampal neuritin injection. In conclusion, the present study suggests that neuritin prevents cognitive defects in AD rat model and its expression level is associated with cognitive resilience.

Conditional Overexpression of Neuritin in Supporting Cell Protects Cochlear Hair Cell and Delays Age-Related Hearing Loss by Enhancing Autophagy

Age-related hearing loss (ARHL) is a highly prevalent, burdensome sensorineural hearing loss closely associated with impaired autophagic influx. Our previous studies revealed that neuritin, a neurotrophic factor primarily expressed in the central nervous system, could alleviate drug-induced damages in hair cells (HCs) and spiral ganglion neurons. However, its effects on ARHL and whether these effects are closely related to autophagy remain unclear. Using the Nrn1 knock-in mice and cultured cochlear basilar membrane (CBM) of the neonatal mouse, we show that neuritin could restore aging-associated hearing loss and alleviate senescence-associated damage in the cochlea. Overexpression of neuritin in support cells (SCs) alleviates the loss of cochlear HCs and nerve fibers, reducing the damage to spiral ganglion neurons and the shifts in ABR's high-frequency threshold. Furthermore, conditional overexpression of neuritin in SCs improves autophagic influx by upregulating the expression of microtubule-associated protein 1 light chain 3 type B (LCB3) protein and downregulating the expression of p21 protein. In cultured neonatal mouse CBM, neuritin administration significantly inhibits D-galactose-induced HC loss, cellular apoptosis, and ROS production and promotes autophagic influx. These effects were weakened when the autophagy inhibitor 3-MA was added. In summary, our results confirm the therapeutic potential of neuritin treatment for ARHL.

MicroRNA profiling reveals novel biomarkers for cardiovascular and psychological health in plateau psycho CVD

This study aimed to explore the expression characteristics of miRNAs in cardiovascular diseases (CVD) and depression within a plateau environment, to better understand their potential role in Plateau Psycho-CVD. A prospective study design was employed to analyze circulating small RNAs from 20 subjects using high-throughput sequencing technology. Participants were divided into four groups (C, PPC, PP, PC) for comparative analysis. Differentially expressed miRNAs were selected for further functional enrichment analysis. The findings revealed that hsa-miR-1976 and hsa-miR-4685-3p were significantly upregulated in patients with Plateau Psycho-CVD and mental health issues. These miRNAs were closely associated with key pathways relevant to cardiovascular and mental health, including the PI3K-Akt and neurotrophin signaling pathways. Additionally, the downregulated miRNAs in the PPC group were linked to increased expression of AKT1 and STAT3, genes associated with bipolar disorder and inflammatory pathways, indicating a potential impact on neural function. This study identifies hsa-miR-1976 and hsa-miR-4685-3p as novel biomarkers for plateau stress dual heart disease, with AKT1 and STAT3 emerging as potential therapeutic targets. These insights pave the way for further research and clinical applications in related fields.

In vitro effects of recombinant human Neuritin on hair cell recovery post-gentamicin injury in SC lineage-tracing models: Involvement of notch and FGFR signaling

Hair cell (HC) loss, frequently induced by ototoxic agents such as gentamicin, leads to irreversible hearing loss. Because of the restricted regenerative capabilities of the mammalian inner ear, the exploration of therapeutic strategies to restore damaged HCs is critically needed. Recombinant human Neuritin (rhNeuritin), a neurotrophic factor with established roles in promoting cell survival and regeneration across various systems, presents itself as a promising therapeutic candidate for HC repair. In this study, we elucidate the protective effects of rhNeuritin on injured HCs and its capacity to facilitate HC regeneration post-damage. Through the use of cochlear Supporting Cell (SC) lineage-tracing models in neonatal mice, we demonstrate that SC trans-differentiation serves as the origin of HC regeneration following damage. Simultaneously, we uncover that rhNeuritin potentiates the proliferation of SC precursor cells. Mechanistic insights reveal that rhNeuritin-induced cochleae exhibit downregulation of the critical Notch pathway mediator, Hes1, and upregulation of the essential FGFR pathway component Erm, which together may underpin HC regeneration and the proliferation of SC precursors. Notably, rhNeuritin demonstrates significant preservation of HC structural integrity. These findings collectively highlight the therapeutic potential of rhNeuritin in addressing hearing loss resulting from HC damage, thereby opening a new avenue for the restoration of auditory function.

Serum neuritin as a predictive biomarker of early neurological deterioration and poor prognosis after spontaneous intracerebral hemorrhage: a prospective cohort study

Objective

Intracerebral hemorrhage (ICH) is a common cerebrovascular disease characterized by high mortality and disability rates. Neuritin, significantly expressed in injured brain tissues, is implicated in the molecular mechanisms underlying acute brain injury. We aimed to explore the prognostic and predictive value of serum neuritin in ICH.

Methods

In this prospective cohort study, serum neuritin levels were measured at admission in 202 patients, on post-ICH days 1, 3, 5, 7, and 10 in 54 of these patients, and at the time of enrollment in 100 healthy controls. The Glasgow Coma Scale (GCS) and hematoma volume were used as severity indicators. A poor prognosis was defined as a modified Rankin Scale (mRS) score of 3-6 at 90 days after ICH. END was defined as a decrease of ≥2 points in the GCS score within 24 h of admission. A multivariate logistic regression model was used to assess the independent relationships between serum neuritin levels, END, and poor prognosis.

Results

Serum neuritin levels were significantly increased at the time of patient admission, continued to rise on day 1, peaked on day 3, and then gradually diminished from day 5 until day 10. The levels remained substantially higher in patients compared to healthy controls throughout the 10-day period. The levels were independently related to GCS scores and hematoma volume. In subgroup analyses, the levels showed a linear relationship with the likelihood of experiencing END and poor prognosis at the 90-day mark after ICH. Additionally, the levels were independently associated with END, ordinal mRS scores, and poor prognosis. Under receiver operating characteristic (ROC) curve analysis, serum neuritin levels effectively predicted both END and poor prognosis. Two models incorporating GCS, hematoma volume, and serum neuritin levels were developed and represented using two nomograms separately to estimate END risks and poor prognosis. These models demonstrated clinical efficiency, stability, and validity in ROC, calibration, and decision curve analyses. Internal validation of the models was conducted using a randomly extracted subset of 101 patients. Furthermore, two specific weighted scoring systems were developed to optimize clinical prediction of poor prognosis and END after ICH.

Conclusion

Elevated serum neuritin levels are strongly associated with disease severity, END, and 90-day poor neurological outcomes following ICH, establishing serum neuritin as a potential prognostic biomarker for ICH.

Integration across biophysical scales identifies molecular and cellular correlates of person-to-person variability in human brain connectivity

Brain connectivity arises from interactions across biophysical scales, ranging from molecular to cellular to anatomical to network level. To date, there has been little progress toward integrated analysis across these scales. To bridge this gap, from a unique cohort of 98 individuals, we collected antemortem neuroimaging and genetic data, as well as postmortem dendritic spine morphometric, proteomic and gene expression data from the superior frontal and inferior temporal gyri. Through the integration of the molecular and dendritic spine morphology data, we identified hundreds of proteins that explain interindividual differences in functional connectivity and structural covariation. These proteins are enriched for synaptic structures and functions, energy metabolism and RNA processing. By integrating data at the genetic, molecular, subcellular and tissue levels, we link specific biochemical changes at synapses to connectivity between brain regions. These results demonstrate the feasibility of integrating data from vastly different biophysical scales to provide a more comprehensive understanding of brain connectivity.

Impact of estradiol in inducing endometrial cancer using RL95-2

BACKGROUND

Endometrial cancer is the most common gynecological malignancy that originates from the inner lining of the uterus and predominantly affects postmenopausal women. Prolonged exposure to estrogen, family history of endometrial cancer, obesity, and hormonal imbalance are some of the risk factors associated with endometrial cancer. In our study, we investigated the effect of estradiol, a potent form of estrogen at various concentrations on endometrial cell line RL95-2.

METHODS

Endometrial cell RL95-2 were cultured in DMEM medium with optimal conditions required to maintain the cells. MTT assay and colony formation assay were further performed after treating the cells with different concentrations of estradiol (1, 10, and 100 nM) and TAM (100 nM). Moreover, the effect of genes regulated by estradiol was also examined using microarray and validated using real-time polymerase chain reaction (qRT-PCR).

RESULTS

Time-dependent MTT assay shows a significant change in the ability of the cells to survive relative to concentrations. Colony formation was found to be directly proportional to the concentration of the estradiol (p < 0.05). Among genes, MMP14 (p = 0.03), SPARCL1 (p = 0.005), and CLU (p = 0.06) showed a significant up-regulation in their expression after estradiol treatment while NRN1 (p < 0.001) showed significant downregulation in expression pattern compared to control. However, the TAM treatment was found to be significantly effective after 72 h (p < 0.001) compared to control and 100 nM E2 (p = 0.0206).

CONCLUSION

Our study suggests that estradiol significantly contributes to regulating the viability, colony formation, and expression of genes associated with endometrial cancer.

Single Cell Transcriptomics-Informed Induced Pluripotent Stem Cells Differentiation to Tenogenic Lineage

During vertebrate embryogenesis, axial tendons develop from the paraxial mesoderm and differentiate through specific developmental stages to reach the syndetome stage. While the main roles of signaling pathways in the earlier stages of the differentiation have been well established, pathway nuances in syndetome specification from the sclerotome stage have yet to be explored. Here, we show stepwise differentiation of human iPSCs to the syndetome stage using chemically defined media and small molecules that were modified based on single cell RNA-sequencing and pathway analysis. We identified a significant population of branching off-target cells differentiating towards a neural phenotype overexpressing Wnt. Further transcriptomics post-addition of a WNT inhibitor at the somite stage and onwards revealed not only total removal of the neural off-target cells, but also increased syndetome induction efficiency. Fine-tuning tendon differentiation in vitro is essential to address the current challenges in developing a successful cell-based tendon therapy.

NRN1 epistasis with BDNF and CACNA1C: mediation effects on symptom severity through neuroanatomical changes in schizophrenia

The expression of Neuritin-1 (NRN1), a neurotrophic factor crucial for neurodevelopment and synaptic plasticity, is enhanced by the Brain Derived Neurotrophic Factor (BDNF). Although the receptor of NRN1 remains unclear, it is suggested that NRN1's activation of the insulin receptor (IR) pathway promotes the transcription of the calcium voltage-gated channel subunit alpha1 C (CACNA1C). These three genes have been independently associated with schizophrenia (SZ) risk, symptomatology, and brain differences. However, research on how they synergistically modulate these phenotypes is scarce. We aimed to study whether the genetic epistasis between these genes affects the risk and clinical presentation of the disorder via its effect on brain structure. First, we tested the epistatic effect of NRN1 and BDNF or CACNA1C on (i) the risk for SZ, (ii) clinical symptoms severity and functionality (onset, PANSS, CGI and GAF), and (iii) brain cortical structure (thickness, surface area and volume measures estimated using FreeSurfer) in a sample of 86 SZ patients and 89 healthy subjects. Second, we explored whether those brain clusters influenced by epistatic effects mediate the clinical profiles. Although we did not find a direct epistatic impact on the risk, our data unveiled significant effects on the disorder's clinical presentation. Specifically, the NRN1-rs10484320 x BDNF-rs6265 interplay influenced PANSS general psychopathology, and the NRN1-rs4960155 x CACNA1C-rs1006737 interaction affected GAF scores. Moreover, several interactions between NRN1 SNPs and BDNF-rs6265 significantly influenced the surface area and cortical volume of the frontal, parietal, and temporal brain regions within patients. The NRN1-rs10484320 x BDNF-rs6265 epistasis in the left lateral orbitofrontal cortex fully mediated the effect on PANSS general psychopathology. Our study not only adds clinical significance to the well-described molecular relationship between NRN1 and BDNF but also underscores the utility of deconstructing SZ into biologically validated brain-imaging markers to explore their mediation role in the path from genetics to complex clinical manifestation.

NRN1 interacts with Notch to increase oncogenic STAT3 signaling in melanoma

BACKGROUND

Melanoma is a highly heterogeneous cancer, in which frequent changes in activation of signaling pathways lead to a high adaptability to ever changing tumor microenvironments. The elucidation of cancer specific signaling pathways is of great importance, as demonstrated by the inhibitor of the common BrafV600E mutation PLX4032 in melanoma treatment. We therefore investigated signaling pathways that were influenced by neurotrophin NRN1, which has been shown to be upregulated in melanoma.

METHODS

Using a cell culture model system with an NRN1 overexpression, we investigated the influence of NRN1 on melanoma cells' functionality and signaling. We employed real time cell analysis and spheroid formation assays, while for investigation of molecular mechanisms we used a kinase phosphorylation kit as well as promotor activity analysis followed by mRNA and protein analysis.

RESULTS

We revealed that NRN1 interacts directly with the cleaved intracellular domain (NICD) of Notch1 and Notch3, causing a potential retention of NICD in the cytoplasm and thereby reducing the expression of its direct downstream target Hes1. This leads to decreased sequestration of JAK and STAT3 in a Hes1-driven phosphorylation complex. Consequently, our data shows less phosphorylation of STAT3 while presenting an accumulation of total protein levels of STAT3 in association with NRN1 overexpression. The potential of the STAT3 signaling pathway to act in both a tumor suppressive and oncogenic manner led us to investigate specific downstream targets - namely Vegf A, Mdr1, cMet - which were found to be upregulated under oncogenic levels of NRN1.

CONCLUSIONS

In summary, we were able to show that NRN1 links oncogenic signaling events between Notch and STAT3 in melanoma. We also suggest that in future research more attention should be payed to cellular regulation of signaling molecules outside of the classically known phosphorylation events.

Neuritin Alleviates Diabetic Retinopathy by Regulating Endoplasmic Reticulum Stress in Rats

BACKGROUND

Neuritin, a small-molecule neurotrophic factor, maintains neuronal cell activity, inhibits apoptosis, promotes process growth, and regulates neural progenitor cell differentiation, migration, and synaptic maturation. Neuritin helps retinal ganglion cells (RGCs) survive optic nerve injury in rats and regenerate axons. However, the role of Neuritin in Diabetic retinopathy (DR) is unclear.

OBJECTIVE

This study is intended to investigate the effect and mechanism of Neuritin in DR. For this purpose, we established DR rat models and injected Neuritin into them. This study provides a potential treatment for diabetic retinopathy.

METHODS

The rat model of DR was established by streptozotocin (STZ) injection, and the effect of Neuritin on DR was detected by intravitreal injection. Histological analysis was performed by H&E and TUNEL methods. The mRNA and protein expressions of endoplasmic reticulum stress (ERS) pathway-related transcription factors were detected by qRT-PCR and western blot. The blood-retinal barrier (BRB) function was assessed using the patch-clamp technique and Evans blue leakage assay.

RESULTS

Neuritin significantly improved the retinal structure, restrained the apoptosis of retinal cells, and protected the normal function of BRB in DR model rats. Mechanistically, Neuritin may function by inhibiting the expression of GRP78, ASK1, Caspase-12, VEGF, and so on.

CONCLUSION

Our results indicate that Neuritin alleviates retinal damage in DR rats via the inactive endoplasmic reticulum pathway. Our study provides a potential treatment for DR.

A Molecular Basis of Human Brain Connectivity

Neuroimaging is commonly used to infer human brain connectivity, but those measurements are far-removed from the molecular underpinnings at synapses. To uncover the molecular basis of human brain connectivity, we analyzed a unique cohort of 98 individuals who provided neuroimaging and genetic data contemporaneous with dendritic spine morphometric, proteomic, and gene expression data from the superior frontal and inferior temporal gyri. Through cellular contextualization of the molecular data with dendritic spine morphology, we identified hundreds of proteins related to synapses, energy metabolism, and RNA processing that explain between-individual differences in functional connectivity and structural covariation. By integrating data at the genetic, molecular, subcellular, and tissue levels, we bridged the divergent fields of molecular biology and neuroimaging to identify a molecular basis of brain connectivity.

One-Sentence Summary

Dendritic spine morphometry and synaptic proteins unite the divergent fields of molecular biology and neuroimaging.

Novel maternal duplication of 6p22.3-p25.3 with subtelomeric 6p25.3 deletion: new clinical findings and genotype-phenotype correlations

BACKGROUND

Copy-number variants (CNVs) drive many neurodevelopmental-related disorders. Although many neurodevelopmental-related CNVs can give rise to widespread phenotypes, it is necessary to identify the major genes contributing to phenotypic presentation. Copy-number variations in chromosome 6, such as independent 6p deletion and 6p duplication, have been reported in several live-born infants and present widespread abnormalities such as intellectual disability, growth deficiency, developmental delay, and multiple dysmorphic facial features. However, a contiguous deletion and duplication in chromosome 6p regions have been reported in only a few cases.

CASE PRESENTATION

In this study, we reported the first duplication of chromosome band 6p25.3-p22.3 with deletion of 6p25.3 in a pedigree. This is the first case reported involving CNVs in these chromosomal regions. In this pedigree, we reported a 1-year-old boy with maternal 6p25-pter duplication characterized by chromosome karyotype. Further analysis using CNV-seq revealed a 20.88-Mb duplication at 6p25.3-p22.3 associated with a contiguous 0.66-Mb 6p25.3 deletion. Whole exome sequencing confirmed the deletion/duplication and identified no pathogenic or likely pathogenic variants related with the patient´s phenotype. The proband presented abnormal growth, developmental delay, skeletal dysplasia, hearing loss, and dysmorphic facial features. Additionally, he presented recurrent infection after birth. CNV-seq using the proband´s parental samples showed that the deletion/duplication was inherited from the proband´s mother, who exhibited a similar phenotype to the proband. When compared with other cases, this proband and his mother presented a new clinical finding: forearm bone dysplasia. The major candidate genes contributing to recurrent infection, eye development, hearing loss features, neurodevelopmental development, and congenital bone dysplasia were further discussed.

CONCLUSIONS

Our results showed a new clinical finding of a contiguous deletion and duplication in chromosome 6p regions and suggested candidate genes associated with phenotypic features, such as FOXC1, SERPINB6, NRN1, TUBB2A, IRF4, and RIPK1.

Histological markers, sickle-shaped blood vessels, myxoid area, and infiltrating growth pattern help stratify the prognosis of patients with myxofibrosarcoma/undifferentiated sarcoma

Myxofibrosarcoma (MFS) and undifferentiated sarcoma (US) have been considered as tumors of the same lineage based on genetic/epigenetic profiling. Although MFS shows a notably better prognosis than US, there are no clear criteria for distinguishing between them. Here, we examined 85 patients with MFS/US and found that tumors with infiltrative growth patterns tended to have more myxoid areas and higher local recurrence rates but fewer distant metastases and better overall survival. Morphologically characteristic sickle-shaped blood vessels, which tended to have fewer αSMA-positive cells, were also observed in these tumors, compared with normal vessels. Based on the incidence of these sickle-shaped blood vessels, we subdivided conventionally diagnosed US into two groups. This stratification was significantly correlated with metastasis and prognosis. RNA sequencing of 24 tumors (9 MFS and 15 US tumors) demonstrated that the proteasome, NF-kB, and VEGF pathways were differentially regulated among these tumors. Expression levels of KDR and NFATC4, which encode a transcription factor responsible for the neuritin-insulin receptor angiogenic signaling, were elevated in the sickle-shaped blood vessel-rich US tumors. These findings indicate that further analyses may help elucidate the malignant potential of MFS/US tumors as well as the development of therapeutic strategies for such tumors.

Establishment and Functional Characterization of Murine Monoclonal Antibodies Recognizing Neuritin

Neuritin represents a neurotrophic factor that is not only important in neuronal development and plasticity but also impacts endothelial angiogenesis, cell migration, tumor growth and the production of antibodies by B cells. We established monoclonal mouse anti-mouse neuritin antibodies by immunizing knock-out mice with two different neuritin-derived peptides. Because neuritin is well conserved between species, these new monoclonal antibodies recognize the neuritin of a wide variety of species, including human. Moreover, they not only recognize specifically surface-bound neuritin expressed by murine follicular regulatory T cells but also the block binding of recombinant neuritin to germinal center B cells. This suggests that these newly generated tools will be of great use in studying neuritin expression and function.

Integration of network pharmacology and molecular docking to explore the molecular mechanism of Cordycepin in the treatment of Alzheimer's disease

Background

Cordycepin is a nucleoside adenosine analog and an active ingredient isolated from the liquid fermentation of Cordyceps. This study sought to explore the mechanism underlying the therapeutic effect of Cordycepin against Alzheimer's disease using network pharmacology and molecular docking technology.

Methods

TCMSP, SYMMAP, CTD, Super-pred, SEA, GeneCards, DisGeNET database, and STRING platform were used to screen and construct the target and protein interaction network of Cordycepin for Alzheimer's disease. The results of Gene Ontology annotation and KEGG pathway enrichment analysis were obtained based on the DAVID database. The Omicshare database was also applied in GO and KEGG pathway enrichment analysis of the key targets. The protein-protein interaction network was constructed using the STRING database, and the potential effective targets for AD were screened based on the degree values. The correlation between the potential targets of Cordycepin in the treatment of AD and APP, MAPT, and PSEN2 was analyzed using (GEPIA) databases. We obtained potential targets related to aging using the Aging Altas database. Molecular docking analysis was performed by AutoDock Vina and Pymol software. Finally, we validated the significant therapeutic targets in the Gene Expression Omnibus (GEO) database.

Results

A total of 74 potential targets of Cordycepin for treating Alzheimer's disease were identified. The potential targets of Cordycepin for the treatment of AD mainly focused on Lipid and atherosclerosis (hsa05417), Platinum drug resistance (hsa01524), Apoptosis (hsa04210), and Pathways in cancer (hsa05200). Our findings suggest that the therapeutic effect of Cordycepin on AD is primarily associated with these biological processes. We obtained 12 potential therapeutic targets for AD using the degree value in Cytoscape. Interestingly, AKT1, MAPK8, BCL2L1, FOXO3, and CTNNB1 were not only significantly associated with pathogenic genes (APP, MAPT, and PSEN2) but also with longevity in Alzheimer's Disease. Thus we speculated that the five target genes were potential core targets mediating the therapeutic effect of Cordycepin against AD. Moreover, molecular docking results analysis showed good binding affinity between Cordycepin and the five core targets. Overall, MAPK8, FOXO3 and CTNNB1 may have significant clinical and treatment implications.

Conclusion

Network pharmacology demonstrated that Cordycepin exerts a therapeutic effect against Alzheimer's disease via multiple targets and signaling pathways and has huge prospects for application in treating neurodegenerative diseases.

Translational approaches to understanding resilience to Alzheimer's disease

Individuals who maintain cognitive function despite high levels of Alzheimer's disease (AD)-associated pathology are said to be 'resilient' to AD. Identifying mechanisms underlying resilience represents an exciting therapeutic opportunity. Human studies have identified a number of molecular and genetic factors associated with resilience, but the complexity of these cohorts prohibits a complete understanding of which factors are causal or simply correlated with resilience. Genetically and phenotypically diverse mouse models of AD provide new and translationally relevant opportunities to identify and prioritize new resilience mechanisms for further cross-species investigation. This review will discuss insights into resilience gained from both human and animal studies and highlight future approaches that may help translate these insights into therapeutics designed to prevent or delay AD-related dementia.

Targeting the Erk1/2 and autophagy signaling easily improved the neurobalst differentiation and cognitive function after young transient forebrain ischemia compared to old gerbils

The hippocampal neurogenesis occurs constitutively throughout adulthood in mammalian species, but declines with age. In this study, we overtly found that the neuroblast proliferation and differentiation in the subgranular zone and the maturation into fully functional and integrated neurons in the granule-cell layer in young gerbils following cerebral ischemia/reperfusion was much more than those in old gerbils. The neurological function and cognitive and memory-function rehabilitation in the young gerbils improved faster than those in the old one. These results demonstrated that, during long term after cerebral ischemia/reperfusion, the ability of neurogenesis and recovery of nerve function in young animals were significantly higher than that in the old animals. We found that, after 14- and 28-day cerebral ischemia/reperfusion, the phosphorylation of MEK1/2, ERK1/2, p90RSK, and MSK1/2 protein levels in the hippocampus of young gerbils was significantly much higher than that of old gerbils. The levels of autophagy-related proteins, including Beclin-1, Atg3, Atg5, and LC3 in the hippocampus were effectively maintained and elevated at 28 days after cerebral ischemia/reperfusion in the young gerbils compared with those in the old gerbils. These results indicated that an increase or maintenance of the phosphorylation of ERK1/2 signal pathway and autophagy-related proteins was closely associated with the neuroblast proliferation and differentiation and the process of maturation into neurons. Further, we proved that neuroblast proliferation and differentiation in the dentate gyrus and cognitive function were significantly reversed in young cerebral ischemic gerbils by administering the ERK inhibitor (U0126) and autophagy inhibitor (3MA). In brief, following experimental young ischemic stroke, the long-term promotion of the neurogenesis in the young gerbil’s hippocampal dentate gyrus by upregulating the phosphorylation of ERK signaling pathway and maintaining autophagy-related protein levels, it overtly improved the neurological function and cognitive and memory function.

Clinicopathological and Preclinical Patient-Derived Model Studies Define High Expression of NRN1 as a Diagnostic and Therapeutic Target for Clear Cell Renal Cell Carcinoma

Background

Acquired therapeutic resistance and metastasis/recurrence remain significant challenge in advance renal cell carcinoma (RCC), thus the establishment of patient-derived cancer models may provide a clue to assess the problem. We recently characterized that neuritogenesis-related protein neuritin 1 (NRN1) functions as an oncogene in testicular germ cell tumor. This study aims to elucidate the role of NRN1 in RCC.

Methods

NRN1 expression in clinical RCC specimens was analyzed based on immunohistochemistry. NRN1-associated genes in RCC were screened by the RNA-sequencing dataset from The Cancer Genome Atlas (TCGA). RCC patient-derived cancer cell (RCC-PDC) spheroid cultures were established and their viabilities were evaluated under the condition of gene silencing/overexpression. The therapeutic effect of NRN1-specific siRNA was evaluated in RCC-PDC xenograft models.

Results

NRN1 immunoreactivity was positively associated with shorter overall survival in RCC patients. In TCGA RCC RNA-sequencing dataset, C-X-C chemokine receptor type 4 (CXCR4), a prognostic and stemness-related factor in RCC, is a gene whose expression is substantially correlated with NRN1 expression. Gain- and loss-of-function studies in RCC-PDC spheroid cultures revealed that NRN1 significantly promotes cell viability along with the upregulation of CXCR4. The NRN1-specific siRNA injection significantly suppressed the proliferation of RCC-PDC-derived xenograft tumors, in which CXCR4 expression is significantly repressed.

Conclusion

NRN1 can be a potential diagnostic and therapeutic target in RCC as analyzed by preclinical patient-derived cancer models and clinicopathological studies.

Astragaloside IV alleviates Schwann cell injury in diabetic peripheral neuropathy by regulating microRNA-155-mediated autophagy

BACKGROUND

MicroRNA-155(miR-155) is closely associated with diabetic peripheral neuropathy (DPN). Astragaloside IV (AST) is a significant extract of Astragalus membranaceus, which has been found to be effective in the treatment of DPN. However, whether astragaloside IV alleviate DPN via regulating miR-155-mediated autophagy remains unclear.

PURPOSE

This study was designed to evaluate the effects of AST on DPN myelin Schwann cells injury and explore the mechanism of AST in treating DPN for the first time.

METHODS

GK rats fed with high-fat diet and RSC96 cells cultured in high glucose were used to establish DPN Schwann cells injury in vivo and in vitro model. The effects of AST on DPN were explored through blood glucose detection, nerve function detection, pathological detection and the expression of Neuritin detected by immunohistochemical. To study the effect of AST on the DPN Schwann cells autophagy and the upstream PI3K/Akt/mTOR pathway, the expressions of beclin-1 and LC3 were detected by western blot (WB) in sciatic nerves and by immunofluorescence (IFC) in RSC96 cells. The real-time polymerase chain reaction (RT-PCR) was applied to detect the expressions of miR-155, ATG5, ATG12 both in vivo and in vitro. The binding effect of miR-155 and target gene PI3KCA was verified by luciferase reporter gene assay. The expressions of PI3K, p-Akt/Akt, p-mTOR/mTOR were detected by WB and the expressions of PI3KCA were detected by RT-PCR in vitro. The apoptosis was detected by flow cytometry. Meanwhile, the influence of miR-155 overexpression and knocked down on the above indicators was also detected in RSC96 cells. At last, further mechanism experiments were conducted to verify the mechanism of AST regulating the autophagy and apoptosis of RSC96 cells.

RESULTS

AST reduced blood glucose levels, alleviated peripheral nerve myelin sheath injury, and improved neurological function in DPN rats. In addition, AST enhanced the autophagy activity and alleviated the apoptosis in RSC96 cell. Mechanism study shown that AST promote autophagy via regulating miR-155-mediated PI3K/Akt/mTOR signaling pathways. AST reduced RSC96 cells apoptosis by promoting autophagy.

CONCLUSION

AST alleviate the myelin sheath injury of DPN caused by the apoptosis of Schwann cells via enhancing autophagy, which was attributed to inhibiting the activation of the PI3K/Akt/mTOR signaling pathway by upregulating miR-155 expression.

Neuritin attenuates oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neuronal injury by promoting autophagic flux

The autophagy/apoptosis interaction has always been a focus of study in pathogenicity models. Neuritin is a neurotrophic factor that is highly expressed primarily in the central nervous system. Our previous study revealed that it protects against apoptosis in cortical neurons subjected to oxygen-glucose deprivation (OGD)/reoxygenation (OGD/R), and later animal experiments revealed that it can increase the expression of the autophagy-related protein LC3. Whether this neuroprotective effect is closely related to autophagy is still unclear. In this study, we hypothesized that neuritin can promote autophagic flux to protect nerve cells after OGD/R. To verify this hypothesis, we induced OGD/R in primary cortical neurons and assessed cell viability by the CCK8 and LDH assays. Cell apoptosis was assessed by Annexin V-FITC/PI, staining, and the contents and mRNA abundances of the autophagy-related proteins LC3 and p62, the apoptotic protein Caspase3 were quantified by Western blotting and RT-PCR. Autophagic flux was assessed by immunofluorescence after RFP-GFP-LC3 virus transfection, and ultrastructural changes in autophagosomes were observed by transmission electron microscopy (TEM). The results showed that cell viability was decreased, apoptosis was increased and autophagy was enhanced after OGD/R. Neuritin significantly increased cell viability, decreased apoptosis, further increased the expression of the autophagic flux-related protein LC3, further decreased p62 expression, and significantly increased the autophagosome number and autophagosome to lysosome ratio. Bafilomycin A1 (BafA1) is a late autophagy inhibitor, aggravated cell damage and apoptosis and counteracted the enhancement of autophagy activation and protective effects of neuritin. In conclusion, neuritin may promote the completion of autophagic flux by ameliorating neuronal damage after OGD/R.

Single-nucleus transcriptome analysis reveals cell-type-specific molecular signatures across reward circuitry in the human brain

Single-cell gene expression technologies are powerful tools to study cell types in the human brain, but efforts have largely focused on cortical brain regions. We therefore created a single-nucleus RNA-sequencing resource of 70,615 high-quality nuclei to generate a molecular taxonomy of cell types across five human brain regions that serve as key nodes of the human brain reward circuitry: nucleus accumbens, amygdala, subgenual anterior cingulate cortex, hippocampus, and dorsolateral prefrontal cortex. We first identified novel subpopulations of interneurons and medium spiny neurons (MSNs) in the nucleus accumbens and further characterized robust GABAergic inhibitory cell populations in the amygdala. Joint analyses across the 107 reported cell classes revealed cell-type substructure and unique patterns of transcriptomic dynamics. We identified discrete subpopulations of D1- and D2-expressing MSNs in the nucleus accumbens to which we mapped cell-type-specific enrichment for genetic risk associated with both psychiatric disease and addiction.

Lack of association of FKBP5 SNPs and haplotypes with susceptibility and treatment response phenotypes in Han Chinese with major depressive disorder: A pilot case-control study (STROBE)

The identification of single-nucleotide polymorphisms (SNPs) in genes putatively related to pathophysiological processes in major depressive disorder (MDD) might improve both diagnosis and personalized treatment strategies eventually leading to more effective interventions. Considering the important role of the glucocorticoid receptor and the related FK506 binding protein 51 (FKBP51) in the pathophysiology of MDD, we aimed to investigate putative associations between variants of FKBP5, the coding gene of FKBP51, with antidepressant treatment resistance and MDD susceptibility.Nine common SNPs of the FKBP5 gene prioritized based on location and, putative or known functions were genotyped in Han Chinese population, including MDD patients with or without antidepressant-treatment resistance and healthy controls. Associations of FKBP5 SNPs with MDD susceptibility and treatment response were examined in the whole group of MDD patients, as well as in subgroups stratified by antidepressant treatment resistance, compared with healthy controls.In total, 181 Han Chinese patients with MDD and 80 healthy controls were recruited. No significant SNP or haplotype associations were observed in the whole patient group. There were nominal significant differences both for the haplotype block with SNPs in strong LD (r2 > 0.8, P = .040) and haplotype block with SNPs in moderate LD (r2 > 0.1, P = .017) between the haplotype distributions of patients with antidepressant treatment resistance (n = 81) and healthy controls, but both significances did not survive multiple testing correction. Furthermore, no specific haplotype could be observed causing a significant difference in any combination between all comparisons.No associations were observed of FKBP5 variants with MDD or antidepressant treatment response. The lack of associations might be due to the relatively small sample size of this study (power ranged from 0.100 to 0.752). A follow-up study will need larger, better phenotyped, and more homogeneous samples to draw a definitive conclusion regarding the involvement of this gene in MDD.

Identification of potential microRNAs and KEGG pathways in denervation muscle atrophy based on meta-analysis

The molecular mechanism of muscle atrophy has been studied a lot, but there is no comprehensive analysis focusing on the denervated muscle atrophy. The gene network that controls the development of denervated muscle atrophy needs further elucidation. We examined differentially expressed genes (DEGs) from five denervated muscle atrophy microarray datasets and predicted microRNAs that target these DEGs. We also included the differentially expressed microRNAs datasets of denervated muscle atrophy in previous studies as background information to identify potential key microRNAs. Finally, we compared denervated muscle atrophy with disuse muscle atrophy caused by other reasons, and obtained the Den-genes which only differentially expressed in denervated muscle atrophy. In this meta-analysis, we obtained 429 up-regulated genes, 525 down-regulated genes and a batch of key microRNAs in denervated muscle atrophy. We found eight important microRNA-mRNA interactions (miR-1/Jun, miR-1/Vegfa, miR-497/Vegfa, miR-23a/Vegfa, miR-206/Vegfa, miR-497/Suclg1, miR-27a/Suclg1, miR-27a/Mapk14). The top five KEGG pathways enriched by Den-genes are Insulin signaling pathway, T cell receptor signaling pathway, MAPK signaling pathway, Toll-like receptor signaling pathway and B cell receptor signaling pathway. Our research has delineated the RNA regulatory network of denervated muscle atrophy, and uncovered the specific genes and terms in denervated muscle atrophy.

Neural Stimulation and Molecular Mechanisms of Plasticity and Regeneration: A Review

Neural stimulation modulates the depolarization of neurons, thereby triggering activity-associated mechanisms of neuronal plasticity. Activity-associated mechanisms in turn play a major role in post-mitotic structure and function of adult neurons. Our understanding of the interactions between neuronal behavior, patterns of neural activity, and the surrounding environment is evolving at a rapid pace. Brain derived neurotrophic factor is a critical mediator of activity-associated plasticity, while multiple immediate early genes mediate plasticity of neurons following bouts of neural activity. New research has uncovered genetic mechanisms that govern the expression of DNA following changes in neural activity patterns, including RNAPII pause-release and activity-associated double stranded breaks. Discovery of novel mechanisms governing activity-associated plasticity of neurons hints at a layered and complex molecular control of neuronal response to depolarization. Importantly, patterns of depolarization in neurons are shown to be important mediators of genetic expression patterns and molecular responses. More research is needed to fully uncover the molecular response of different types of neurons-to-activity patterns; however, known responses might be leveraged to facilitate recovery after neural damage. Physical rehabilitation through passive or active exercise modulates neurotrophic factor expression in the brain and spinal cord and can initiate cortical plasticity commensurate with functional recovery. Rehabilitation likely relies on activity-associated mechanisms; however, it may be limited in its application. Electrical and magnetic stimulation direct specific activity patterns not accessible through passive or active exercise and work synergistically to improve standing, walking, and forelimb use after injury. Here, we review emerging concepts in the molecular mechanisms of activity-derived plasticity in order to highlight opportunities that could add value to therapeutic protocols for promoting recovery of function after trauma, disease, or age-related functional decline.

Activating Transcription Factor 3 (ATF3) Protects Retinal Ganglion Cells and Promotes Functional Preservation After Optic Nerve Crush

Purpose

To investigate the possible role of activating transcription factor 3 (ATF3) in retinal ganglion cell (RGC) neuroprotection and optic nerve regeneration after optic nerve crush (ONC).

Methods

Overexpression of proteins of interest (ATF3, phosphatase and tensin homolog [PTEN], placental alkaline phosphatase, green fluorescent protein) in the retina was achieved by intravitreal injections of recombinant adenovirus-associated viruses (rAAVs) expressing corresponding proteins. The number of RGCs and αRGCs was evaluated by immunostaining retinal sections and whole-mount retinas with antibodies against RNA binding protein with multiple splicing (RBPMS) and osteopontin, respectively. Axonal regeneration was assessed via fluorophore-coupled cholera toxin subunit B labeling. RGC function was evaluated by recording positive scotopic threshold response.

Results

The level of ATF3 is preferentially elevated in osteopontin⁺/RBPMS⁺ αRGCs following ONC. Overexpression of ATF3 by intravitreal injection of rAAV 2 weeks before ONC promoted RBPMS⁺ RGC survival and preserved RGC function as assessed by positive scotopic threshold response recordings 2 weeks after ONC. However, overexpression of ATF3 and simultaneous downregulation of PTEN, a negative regulator of the mTOR pathway, combined with ONC, only moderately promoted short distance RGC axon regeneration (200 μm from the lesion site) but did not provide additional RGC neuroprotection compared with PTEN downregulation alone.

Conclusions

These results reveal a neuroprotective effect of ATF3 in the retina following injury and identify ATF3 as a promising agent for potential treatments of optic neuropathies.

Adaptive Fisher method detects dense and sparse signals in association analysis of SNV sets

BACKGROUND

With the development of next generation sequencing (NGS) technology and genotype imputation methods, statistical methods have been proposed to test a set of genomic variants together to detect if any of them is associated with the phenotype or disease. In practice, within the set, there is an unknown proportion of variants truly causal or associated with the disease. There is a demand for statistical methods with high power in both dense and sparse scenarios, where the proportion of causal or associated variants is large or small respectively.

RESULTS

We propose a new association test - weighted Adaptive Fisher (wAF) that can adapt to both dense and sparse scenarios by adding weights to the Adaptive Fisher (AF) method we developed before. Using simulation, we show that wAF enjoys comparable or better power to popular methods such as sequence kernel association tests (SKAT and SKAT-O) and adaptive SPU (aSPU) test. We apply wAF to a publicly available schizophrenia dataset, and successfully detect thirteen genes. Among them, three genes are supported by existing literature; six are plausible as they either relate to other neurological diseases or have relevant biological functions.

CONCLUSIONS

The proposed wAF method is a powerful disease-variants association test in both dense and sparse scenarios. Both simulation studies and real data analysis indicate the potential of wAF for new biological findings.