EFhd2, a Protein Linked to Alzheimer's Disease and Other Neurological Disorders

EFhd2 co-aggregates with monomeric and filamentous tau in vitro

Tauopathies are characterized by the abnormal buildup of tau protein, with early oligomeric forms associated with neurodegeneration and the later neurofibrillary tangles possibly conferring neuroprotection. The molecular mechanisms governing the formation of these tau species are unclear. Lately, there has been an increased focus on examining the interactions between tau and other proteins, along with their influence on the aggregation of tau. Our previous work revealed EFhd2's association with pathological tau in animal models and tauopathy brains. Herein, we examined the impact of EFhd2 on monomeric and filamentous tau in vitro. The results demonstrated that EFhd2 incubation with monomeric full length human tau (hTau40) formed amorphous aggregates, where both EFhd2 and hTau40 colocalized. Moreover, EFhd2 is entangled with arachidonic acid (ARA)-induced filamentous hTau40. Furthermore, EFhd2-induced aggregation with monomeric and filamentous hTau40 is EFhd2 concentration dependent. Using sandwich ELISA assays, we assessed the reactivity of TOC1 and Alz50-two conformation-specific tau antibodies-to EFhd2-hTau40 aggregates (in absence and presence of ARA). No TOC1 signal was detected in EFhd2 aggregates with monomeric hTau40 whereas EFhd2 aggregates with hTau in the presence of ARA showed a higher signal compared to hTau40 filaments. In contrast, EFhd2 aggregates with both monomeric and filamentous hTau40 reduced Alz50 reactivity. Taken together, our results illustrate for the first time that EFhd2, a tau-associated protein, interacts with monomeric and filamentous hTau40 to form large aggregates that are starkly different from tau oligomers and filaments. Given these findings and previous research, we hypothesize that EFhd2 may play a role in the formation of tau aggregates. Nevertheless, further in vivo studies are imperative to test this hypothesis.

Transcriptomic analysis reveals sex-specific patterns in the hippocampus in Alzheimer's disease

Background

The hippocampus, vital for memory and learning, is among the first brain regions affected in Alzheimer's Disease (AD) and exhibits adult neurogenesis. Women face twice the risk of developing AD compare to men, making it crucial to understand sex differences in hippocampal function for comprehending AD susceptibility.

Methods

We conducted a comprehensive analysis of bulk mRNA postmortem samples from the whole hippocampus (GSE48350, GSE5281) and its CA1 and CA3 subfields (GSE29378). Our aim was to perform a comparative molecular signatures analysis, investigating sex-specific differences and similarities in the hippocampus and its subfields in AD. This involved comparing the gene expression profiles among: (a) male controls (M-controls) vs. female controls (F-controls), (b) females with AD (F-AD) vs. F-controls, (c) males with AD (M-AD) vs. M-controls, and (d) M-AD vs. F-AD. Furthermore, we identified AD susceptibility genes interacting with key targets of menopause hormone replacement drugs, specifically the ESR1 and ESR2 genes, along with GPER1.

Results

The hippocampal analysis revealed contrasting patterns between M-AD vs. M-controls and F-AD vs. F-controls, as well as M-controls vs. F-controls. Notably, BACE1, a key enzyme linked to amyloid-beta production in AD pathology, was found to be upregulated in M-controls compared to F-controls in both CA1 and CA3 hippocampal subfields. In M-AD vs. M-controls, the GABAergic synapse was downregulated, and the Estrogen signaling pathway was upregulated in both subfields, unlike in F-AD vs. F-controls. Analysis of the whole hippocampus also revealed upregulation of the GABAergic synapse in F-AD vs. F-controls. While direct comparison of M-AD vs. F-AD, revealed a small upregulation of the ESR1 gene in the CA1 subfield of males. Conversely, F-AD vs. F-controls exhibited downregulation of the Dopaminergic synapse in both subfields, while the Calcium signaling pathway showed mixed regulation, being upregulated in CA1 but downregulated in CA3, unlike in M-AD vs. M-controls. The upregulated Estrogen signaling pathway in M-AD, suggests a compensatory response to neurodegenerative specifically in males with AD. Our results also identified potential susceptibility genes interacting with ESR1 and ESR2, including MAPK1, IGF1, AKT1, TP53 and CD44.

Conclusion

These findings underscore the importance of sex-specific disease mechanisms in AD pathogenesis. Region-specific analysis offers a more detailed examination of localized changes in the hippocampus, enabling to capture sex-specific molecular patterns in AD susceptibility and progression.

EFHD2 suppresses intestinal inflammation by blocking intestinal epithelial cell TNFR1 internalization and cell death

TNF acts as one pathogenic driver for inducing intestinal epithelial cell (IEC) death and substantial intestinal inflammation. How the IEC death is regulated to physiologically prevent intestinal inflammation needs further investigation. Here, we report that EF-hand domain-containing protein D2 (EFHD2), highly expressed in normal intestine tissues but decreased in intestinal biopsy samples of ulcerative colitis patients, protects intestinal epithelium from TNF-induced IEC apoptosis. EFHD2 inhibits TNF-induced apoptosis in primary IECs and intestinal organoids (enteroids). Mice deficient of Efhd2 in IECs exhibit excessive IEC death and exacerbated experimental colitis. Mechanistically, EFHD2 interacts with Cofilin and suppresses Cofilin phosphorylation, thus blocking TNF receptor I (TNFR1) internalization to inhibit IEC apoptosis and consequently protecting intestine from inflammation. Our findings deepen the understanding of EFHD2 as the key regulator of membrane receptor trafficking, providing insight into death receptor signals and autoinflammatory diseases.

Single-Cell Transcriptome Analysis Reveals Development-Specific Networks at Distinct Synchronized Antral Follicle Sizes in Sheep Oocytes

The development of the ovarian antral follicle is a complex, highly regulated process. Oocytes orchestrate and coordinate the development of mammalian ovarian follicles, and the rate of follicular development is governed by a developmental program intrinsic to the oocyte. Characterizing oocyte signatures during this dynamic process is critical for understanding oocyte maturation and follicular development. Although the transcriptional signature of sheep oocytes matured in vitro and preovulatory oocytes have been previously described, the transcriptional changes of oocytes in antral follicles have not. Here, we used single-cell transcriptomics (SmartSeq2) to characterize sheep oocytes from small, medium, and large antral follicles. We characterized the transcriptomic landscape of sheep oocytes during antral follicle development, identifying unique features in the transcriptional atlas, stage-specific molecular signatures, oocyte-secreted factors, and transcription factor networks. Notably, we identified the specific expression of 222 genes in the LO, 8 and 6 genes that were stage-specific in the MO and SO, respectively. We also elucidated signaling pathways in each antral follicle size that may reflect oocyte quality and in vitro maturation competency. Additionally, we discovered key biological processes that drive the transition from small to large antral follicles, revealing hub genes involved in follicle recruitment and selection. Thus, our work provides a comprehensive characterization of the single-oocyte transcriptome, filling a gap in the mapping of the molecular landscape of sheep oogenesis. We also provide key insights into the transcriptional regulation of the critical sizes of antral follicular development, which is essential for understanding how the oocyte orchestrates follicular development.

Modulation of biomolecular phase behavior by metal ions

Liquid-liquid phase separation (LLPS) appears to be a newly appreciated aspect of the cellular organization of biomolecules that leads to the formation of membraneless organelles (MLOs). MLOs generate distinct microenvironments where particular biomolecules are highly concentrated compared to those in the surrounding environment. Their thermodynamically driven formation is reversible, and their liquid nature allows them to fuse with each other. Dysfunctional biomolecular condensation is associated with human diseases. Pathological states of MLOs may originate from the mutation of proteins or may be induced by other factors. In most aberrant MLOs, transient interactions are replaced by stronger and more rigid interactions, preventing their dissolution, and causing their uncontrolled growth and dysfunction. For these reasons, there is great interest in identifying factors that modulate LLPS. In this review, we discuss an enigmatic and mostly unexplored aspect of this process, namely, the regulatory effects of metal ions on the phase behavior of biomolecules.

Differential Cellular Interactome in Schizophrenia and Bipolar Disorder-Discriminatory Biomarker Role

Schizophrenia (SCH) and bipolar disorder (BD) are two of the most important psychiatric pathologies due to their high population incidence and disabling power, but they also present, mainly in their debut, high clinical similarities that make their discrimination difficult. In this work, the differential oxidative stress, present in both disorders, is shown as a concatenator of the systemic alterations-both plasma and erythrocyte, and even at the level of peripheral blood mononuclear cells (PBMC)-in which, for the first time, the different affectations that both disorders cause at the level of the cellular interactome were observed. A marked erythrocyte antioxidant imbalance only present in SCH generalizes to oxidative damage at the plasma level and shows a clear impact on cellular involvement. From the alteration of protein synthesis to the induction of death by apoptosis, including proteasomal damage, mitochondrial imbalance, and autophagic alteration, all the data show a greater cellular affectation in SCH than in BD, which could be linked to increased oxidative stress. Thus, patients with SCH in our study show increased endoplasmic reticulum (ER)stress that induces increased proteasomal activity and a multifactorial response to misfolded proteins (UPR), which, together with altered mitochondrial activity, generating free radicals and leading to insufficient energy production, is associated with defective autophagy and ultimately leads the cell to a high apoptotic predisposition. In BD, however, oxidative damage is much milder and without significant activation of survival mechanisms or inhibition of apoptosis. These clear differences identified at the molecular and cellular level between the two disorders, resulting from progressive afflictions in which oxidative stress can be both a cause and a consequence, significantly improve the understanding of both disorders to date and are essential for the development of targeted and preventive treatments.

Clinical characterization of EFHD2 (swiprosin-1) in Glioma-associated macrophages and its role in regulation of immunosuppression

Glioblastoma has been extensively studied due to its high mortality and short survival. The evolution mechanism of tumor-associated macrophages (TAMs) to Glioma-associated microglia and macrophages (GAMs) in the tumor microenvironment (TME) remains to be elucidated. The tumor cell-to-cell interaction patterns have not been well defined yet. The EF-Hand Domain Family Member D2 (EFHD2) has been reported to be differentially expressed as an immunomodulatory molecule in a variety of cancers. But large-scale clinical data from multiple ethnic communities have not been used to investigate the role of EFHD2 in glioma. RNA-seq data from 313 or 657 glioma patients from the Chinese Glioma Genome Atlas (CGGA) database and 603 glioma patients from the Cancer Genome Atlas (TCGA) database were analyzed retrospectively. Cell localization was performed using single-cell sequencing data from the CGGA database and the GSE131928 dataset. Mouse glioma cell lines and primary macrophages isolated from Efhd2 knockout mice were co-cultured to validate the immunomodulatory effects of EFHD2 on macrophages and the remodeling of TME of glioblastoma. EFHD2 is enriched in high-grade gliomas, isocitrate dehydrogenase wild-type, and 1p/19q non-co-deficient gliomas. It is a potential biomarker of glioma-proneuronal subtypes and an independent prognostic factor for overall survival in patients with malignant glioblastoma. EFHD2 regulates the monocyte-macrophage system function and positively correlates with immunosuppressive checkpoints. Further experimental data demonstrates that Efhd2 influences the polarization state of GAMs and inhibits the secretion of TGF-β1. In vitro experiments have revealed that macrophages lacking Efhd2 suppress the vitality of two glioma cell lines and decelerate the growth of glioma xenografts. In conclusion, EFHD2 promises to be a key target for TME-related immunotherapy.

Structural and biochemical insights into Zn2+-bound EF-hand proteins, EFhd1 and EFhd2

EF-hand proteins, which contain a Ca2+-binding EF-hand motif, are involved in regulating diverse cellular functions. Ca2+ binding induces conformational changes that modulate the activities of EF-hand proteins. Moreover, these proteins occasionally modify their activities by coordinating metals other than Ca2+, including Mg2+, Pb2+ and Zn2+, within their EF-hands. EFhd1 and EFhd2 are homologous EF-hand proteins with similar structures. Although separately localized within cells, both are actin-binding proteins that modulate F-actin rearrangement through Ca2+-independent actin-binding and Ca2+-dependent actin-bundling activity. Although Ca2+ is known to affect the activities of EFhd1 and EFhd2, it is not known whether their actin-related activities are affected by other metals. Here, the crystal structures of the EFhd1 and EFhd2 core domains coordinating Zn2+ ions within their EF-hands are reported. The presence of Zn2+ within EFhd1 and EFhd2 was confirmed by analyzing anomalous signals and the difference between anomalous signals using data collected at the peak positions as well as low-energy remote positions at the Zn K-edge. EFhd1 and EFhd2 were also found to exhibit Zn2+-independent actin-binding and Zn2+-dependent actin-bundling activity. This suggests the actin-related activities of EFhd1 and EFhd2 could be regulated by Zn2+ as well as Ca2+.

Minimal gene set discovery in single-cell mRNA-seq datasets with ActiveSVM

Sequencing costs currently prohibit the application of single-cell mRNA-seq to many biological and clinical analyses. Targeted single-cell mRNA-sequencing reduces sequencing costs by profiling reduced gene sets that capture biological information with a minimal number of genes. Here we introduce an active learning method that identifies minimal but highly informative gene sets that enable the identification of cell types, physiological states and genetic perturbations in single-cell data using a small number of genes. Our active feature selection procedure generates minimal gene sets from single-cell data by employing an active support vector machine (ActiveSVM) classifier. We demonstrate that ActiveSVM feature selection identifies gene sets that enable ~90% cell-type classification accuracy across, for example, cell atlas and disease-characterization datasets. The discovery of small but highly informative gene sets should enable reductions in the number of measurements necessary for application of single-cell mRNA-seq to clinical tests, therapeutic discovery and genetic screens.

EF-Hand Domain-Containing Protein D2 (EFHD2) Correlates with Immune Infiltration and Predicts the Prognosis of Patients: A Pan-Cancer Analysis

Background

EF-hand domain-containing protein D2 (EFHD2) has recently been reported to participate in initiation of cancer. More evidence indicates that EFHD2 plays an important role in tumors, but the pan-cancer analysis of EFHD2 is still very limited.

Methods

In this study, we downloaded the original mRNA expression data and SNP data of 33 kinds of tumor data. The gene expression data of different tissues were downloaded from the GTEX database, combined with TCGA data and corrected to calculate the difference of gene expression. The data of total survival time (OS) and progression-free survival (PFS) of TCGA patients were downloaded from the Xena database to further survey the relationship between the EFHD2 expression and prognosis. The CIBERSORT algorithm was used to analyze the RNA-seq data of 33 kinds of cancer patients in different subgroups. In this study, NCI-60 drug sensitivity data and RNA-seq data were downloaded to explore the relationship between genes and common antineoplastic drug sensitivity through correlation analysis. In this study, GSEA analysis was carried out from the Molecular Signature database through the packages of "clusterprofiler" and "enrichplot." By comparing the differences of signal pathways between high and low gene expression groups, the possible molecular mechanism of prognostic differences among 33 kinds of tumors was determined.

Results

Our results indicated that EFHD2 was highly expressed in 23 kinds of tumors. In addition, EFHD2 was associated with stage in many kinds of tumors. The expression of EFHD2 was closely related to the OS of 12 kinds of cancer patients. In addition, Kaplan-Meier- (KM-) plot survival analysis indicated that the high expression of EFHD2 was related to the poor OS of 5 kinds of cancer, and the expression of EFHD2 was closely related to the PFI of 5 kinds of cancer patients. The expression of EFHD2 was closely related to immune infiltration, among which 18 cancers were significantly correlated with CD8T cells, 14 cancers were significantly correlated with T regulatory (Tregs) cells, 15 cancers were significantly correlated with CD4 memory activated Tcells, and EFHD2 was significantly correlated with common tumor-related regulatory genes such as TGF beta signaling, TNFA signaling, hypoxia, scorch death, DNA repair, autophagy, and iron death-related genes. The expression level of EFHD2 was significantly correlated with each tumor of TMB, including STAD, SARC, ACC, THYM, KICH, THCA, and TGCT. In MSI, there were significant differences in THYM, STAD, THCA, and TGCT. We used the CellMiner database to explore the sensitivity between EFHD2 gene and common antineoplastic drugs and found that the prediction of high expression of EFHD2 was related to the resistance of many antineoplastic drugs. In renal cell carcinoma, the high expression of EFHD2 is mainly concentrated in ALLOGRAFT_REJECTION, REACTIVE_OXYGEN_SPECIES_PATHWAY, INTERFERON_GAMMA_RESPONSE, IL6_JAK_STAT3_SIGNALING, INTERFERON_ALPHA_RESPONSE, and other signal pathways. GO results showed that the genes were mainly enriched in response to interferon-gamma, antigen processing and presentation, cellular response to interferon-gamma, and other pathways. KEGG results demonstrated that EFHD2 was mainly rich in phagosome, Epstein-Barr virus infection, Staphylococcus aureus infection, and other pathways. The results of Kaplan-Meier survival analysis demonstrated that the high expression of EFHD2 was significantly related to the poor prognosis.

Conclusion

Our findings highlight the predictive value of EFHD2 in cancer and provide a potential research direction for elucidating the role of EFHD2 in tumorigenesis and drug resistance.

Role of Swiprosin-1/EFHD2 as a biomarker in the development of chronic diseases

Swiprosin-1 or EFHD2, is a Ca²⁺ binding actin protein and its expression has been shown to be distinct in various cell types. The expression of swiprosin-1 is upregulated during the activation of immune cells, epithelial and endothelial cells. The expression of swiprosin-1 is regulated by diverse signaling pathways that are contingent upon the specific type of cells. The aim of this review is to summarize and provide an overview of the role of swiprosin-1 in pathophysiological conditions of cancers, cardiovascular diseases, diabetic nephropathy, neuropsychiatric diseases, and in the process of inflammation, immune response, and inflammatory diseases. Novel approaches for the targeting of swiprosin-1 as a biomarker in the early detection and prevention of various development of chronic diseases are also explored.

Swiprosin-1 deficiency in macrophages alleviated atherogenesis

Macrophages play a vital role in the development of atherosclerosis. Previously, we have found that swiprosin-1 was abundantly expressed in macrophages. Here, we investigated the role of swiprosin-1 expressed in macrophages in atherogenesis. Bone marrow transplantation was performed from swiprosin-1-knockout (Swp-/-) mice and age-matched ApoE-/- mice. Atherosclerotic lesion, serum lipid, and interleukin-β (IL-β) levels were detected. In vitro, the peritoneal macrophages isolated from Swp-/- and wild-type mice were stimulated with oxidized low-density lipoprotein (ox-LDL) and the macrophage of foam degree, cellular lipid content, apoptosis, inflammatory factor, migration, and autophagy were determined. Our results showed that swiprosin-1 was mainly expressed in macrophages of atherosclerotic plaques in aorta from ApoE-/- mice fed with high-cholesterol diet (HCD). The expression of swiprosin-1 in the foaming of RAW264.7 macrophages gradually increased with the increase of the concentration and time stimulated with ox-LDL. Atherosclerotic plaques, accumulation of macrophages, collagen content, serum total cholesterol, LDL, and IL-β levels were decreased in Swp-/- → ApoE-/- mice compared with Swp+/+ → ApoE-/- mice fed with HCD for 16 weeks. The macrophage foam cell formation and cellular cholesterol accumulation were reduced, while the lipid uptake and efflux increased in macrophages isolated from Swp-/- compared to wild-type mice treated with ox-LDL. Swiprosin-1 deficiency in macrophages could inhibit apoptosis, inflammation, migration, and promote autophagy. Taken together, our results demonstrated that swiprosin-1 deficiency in macrophages could alleviate the development and progression of AS. The role of swiprosin-1 may provide a promising new target for ameliorating AS.

EFhd2 brain interactome reveals its association with different cellular and molecular processes

EFhd2 is a conserved calcium-binding protein that is highly expressed in the central nervous system. We have shown that EFhd2 interacts with tau protein, a key pathological hallmark in Alzheimer's disease and related dementias. However, EFhd2's physiological and pathological functions in the brain are still poorly understood. To gain insights into its physiological function, we identified proteins that co-immunoprecipitated with EFhd2 from mouse forebrain and hindbrain, using tandem mass spectrometry (MS). In addition, quantitative mass spectrometry was used to detect protein abundance changes due to the deletion of the Efhd2 gene in mouse forebrain and hindbrain regions. Our data show that mouse EFhd2 is associated with cytoskeleton components, vesicle trafficking modulators, cellular stress response-regulating proteins, and metabolic proteins. Moreover, proteins associated with the cytoskeleton, vesicular transport, calcium signaling, stress response, and metabolic pathways showed differential abundance in Efhd2^(-/-) mice. This study presents, for the first time, an EFhd2 brain interactome that it is associated with different cellular and molecular processes. These findings will help prioritize further studies to investigate the mechanisms by which EFhd2 modulates these processes in physiological and pathological conditions of the nervous system.

EFHD2 contributes to non-small cell lung cancer cisplatin resistance by the activation of NOX4-ROS-ABCC1 axis

Recurrence and metastasis remain the major cause of cancer mortality. Even for early-stage lung cancer, adjuvant chemotherapy yields merely slight increase to patient survival. EF-hand domain-containing protein D2 (EFHD2) has recently been implicated in recurrence of patients with stage I lung adenocarcinoma. In this study, we investigated the correlation between EFHD2 and chemoresistance in non-small cell lung cancer (NSCLC). High expression of EFHD2 was significantly associated with poor overall survival of NSCLC patients with chemotherapy in in silica analysis. Ectopic EFHD2 overexpression increased cisplatin resistance, whereas EFHD2 knockdown improved chemoresponse. Mechanistically, EFHD2 induced the production of NADPH oxidase 4 (NOX4) and in turn the increase of intracellular reactive oxygen species (ROS), consequently activating membrane expression of the ATP-binding cassette subfamily C member 1 (ABCC1) for drug efflux. Non-steroidal anti-inflammatory drug (NSAID) ibuprofen suppressed EFHD2 expression by leading to the proteasomal and lysosomal degradation of EFHD2 through a cyclooxygenase (COX)-independent mechanism. Combining ibuprofen with cisplatin enhanced antitumor responsiveness in a murine xenograft model in comparison with the individual treatment. In conclusion, we demonstrate that EFHD2 promotes chemoresistance through the NOX4-ROS-ABCC1 axis and therefore developing EFHD2-targeting strategies may offer a new avenue to improve adjuvant chemotherapy of lung cancer.

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EFHD2 increases resistance of lung cancer to cisplatin.

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EFHD2 enhances the NOX4-ROS-ABCC1signalingfor cisplatin efflux.

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Ibuprofen suppresses EFHD2 through both proteasomal and lysosomal degradationmechanisms

EFhd2 Affects Tau Liquid-Liquid Phase Separation

The transition of tau proteins from its soluble physiological conformation to the pathological aggregate forms found in Alzheimer's disease and related dementias, is poorly understood. Therefore, understanding the process that modulates the formation of toxic tau oligomers and their conversion to putative neuroprotective neurofibrillary tangles will lead to better therapeutic strategies. We previously identified that EFhd2 is associated with aggregated tau species in AD brains and the coiled-coil domain in EFhd2 mediates the interaction with tau. To further characterize the association between EFhd2 and tau, we examined whether EFhd2 could affect the liquid-liquid phase separation properties of tau under molecular crowding conditions. We demonstrate that EFhd2 alters tau liquid phase behavior in a calcium and coiled-coil domain dependent manner. Co-incubation of EFhd2 and tau in the absence of calcium leads to the formation of solid-like structures containing both proteins, while in the presence of calcium these two proteins phase separate together into liquid droplets. EFhd2's coiled-coil domain is necessary to alter tau's liquid phase separation, indicating that protein-protein interaction is required. The results demonstrate that EFhd2 affects the liquid-liquid phase separation of tau proteins in vitro, suggesting that EFhd2 modulates the structural dynamics of tau proteins.

Tau's Three-Repeat Domain and EFhd2 Co-incubation Leads to Increased Thioflavin Signal

Aggregation of the protein tau is a pathological hallmark of Alzheimer’s disease (AD) and related disorders. However, the molecular mechanisms that lead to tau protein aggregation are still unclear. Previously, we showed that EFhd2 protein is associated with pathological aggregated forms of tau in AD brain. Further, immuno-gold analyses of purified tau aggregates showed that EFhd2 co-localized with filamentous tau structures. We demonstrated that EFhd2’s coiled-coil domain is required for its association with tau proteins. However, it is unknown the role that EFhd2 plays in tau aggregation. Here, we show that incubation of K19-tau with substoichiometric amount of EFhd2 promote the formation of amyloid structures in vitro. The result suggests that EFhd2 may play a role in the biogenesis of aggregated tau.

Impact of Swiprosin-1/Efhd2 on Adult Hippocampal Neurogenesis

Swiprosin-1/Efhd2 (Efhd2) is highly expressed in the CNS during development and in the adult. EFHD2 is regulated by Ca²⁺ binding, stabilizes F-actin, and promotes neurite extension. Previous studies indicated a dysregulation of EFHD2 in human Alzheimer's disease brains. We hypothesized a detrimental effect of genetic ablation of Efhd2 on hippocampal integrity and specifically investigated adult hippocampal neurogenesis. Efhd2 was expressed throughout adult neuronal development and in mature neurons. We observed a severe reduction of the survival of adult newborn neurons in Efhd2 knockouts, starting at the early neuroblast stage. Spine formation and dendrite growth of newborn neurons were compromised in full Efhd2 knockouts, but not upon cell-autonomous Efhd2 deletion. Together with our finding of severe hippocampal tauopathy in Efhd2 knockout mice, these data connect Efhd2 to impaired synaptic plasticity as present in Alzheimer's disease and identify a role of Efhd2 in neuronal survival and synaptic integration in the adult hippocampus.

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Efhd2 is expressed in the dentate gyrus and its loss reduces adult neurogenesis

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Reduced neurite complexity and spine density in new neurons of Efhd2 knockout mice

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Role of cell-extrinsic EFHD2 for dendrite morphology of adult newborn neurons

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Increased levels of pathological TAU in the hippocampus of Efhd2 knockout mice

Exploring Potential Biomarkers Underlying Pathogenesis of Alzheimer's Disease by Differential Co-expression Analysis

BACKGROUND

Alzheimer's Disease (AD) is the most common form of dementia in the elderly. Due to the facts that biological causes of AD are complex in addition to increasing rates of AD worldwide, a deeper understanding of AD etiology is required for AD treatment and diagnosis.

METHODS

To identify molecular pathological alterations in AD brains, GSE36980 series containing microarray data samples from temporal cortex, frontal cortex and hippocampus were downloaded from Gene Expression Omnibus (GEO) database and valid gene symbols were subjected to building a gene co-expression network by a bioinformatics tool known as differential regulation from differential co-expression (DCGL) software package. Then, a network-driven integrative analysis was performed to find significant genes and underlying biological terms.

RESULTS

A total of 17088 unique genes were parsed into three independent differential co-expression networks. As a result, a small number of differentially co-regulated genes mostly in frontal and hippocampus lobs were detected as potential biomarkers related to AD brains. Ultimately differentially co-regulated genes were enriched in biological terms including response to lipid and fatty acid and pathways mainly signaling pathway such as G-protein signaling pathway and glutamate receptor groups II and III. By conducting co-expression analysis, our study identified multiple genes that may play an important role in the pathogenesis of AD.

CONCLUSION

The study aimed to provide a systematic understanding of the potential relationships among these genes and it is hoped that it could aid in AD biomarker discovery.

EFHD2 promotes epithelial-to-mesenchymal transition and correlates with postsurgical recurrence of stage I lung adenocarcinoma

Surgery is the only curative treatment for early-stage non-small cell lung cancer (NSCLC) patients. However, approximately one-third of these patients develop recurrence, which remains the main cause of mortality in the postsurgical treatment of NSCLC. Many molecular markers have been proposed to predict recurrence of early-stage disease, but no marker has demonstrated sufficient reliability for clinical application. In the present study, the novel protein EF-hand domain-containing protein D2 (EFHD2) was identified as expressed in highly metastatic tumor cells. EFHD2 increased the formation of protrusive invadopodia structures and cell migration and invasion abilities and promoted the epithelial-to-mesenchymal transition (EMT) character of lung adenocarcinoma cells. We demonstrated that the mechanism of EFHD2 in enhancing EMT occurs partly through inhibition of caveolin-1 (CAV1) for cancer progression. The expression of EFHD2 was significantly correlated with postsurgical recurrence of patients with stage I lung adenocarcinoma in the Kaplan-Meier-plotter cancer database search and our retrospective cohort study (HR, 6.14; 95% CI, 2.40-15.74; P < 0.001). Multivariate Cox regression analysis revealed that EFHD2 expression was an independent clinical predictor for this disease. We conclude that EFHD2 expression is associated with increased metastasis and EMT and could serve as an independent marker to predict postsurgical recurrence of patients with stage I lung adenocarcinoma.

CHI3L1 and CHI3L2 overexpression in motor cortex and spinal cord of sALS patients

BACKGROUND

Amyotrophic Lateral Sclerosis (ALS) is a rapidly progressive neurodegenerative disease characterized by the degeneration and death of upper (UMN) and lower (LMN) motor neurons. In the last decade, it has been shown that Chitinases are an important prognostic indicator of neuro-inflammatory damage induced by microglia and astrocytes.

MATERIALS AND METHODS

We analyzed microarray datasets obtained from the Array Express in order to verify the expression levels of CHI3L1 and CHI3L2 in motor cortex biopsies of sALS patients with different survival times. We also divided the sALS patients into smokers and non-smokers. In order to extend our analysis, we explored two additional microarray datasets, GSE833 and GSE26927, of post-mortem spinal cord biopsies from sALS patients.

RESULTS

The analysis showed that CHI3L1 and CHI3L2 expression levels were significantly upregulated in the motor cortex of sALS patients, compared to the healthy controls. Moreover, their expression levels were negatively correlated with survival time. Interesting results were obtained when we compared the expression levels of Chitinases among smokers. We showed that CHI3L1 and CHI3L2 were significantly upregulated in sALS smokers compared to non-smokers. Furthermore, we found that four genes belonging to the Chitinases network (SERPINA3, C1s, RRAD, HLA-DQA1) were significantly upregulated in the motor cortex of sALS patients and positively correlated with Chitinases expression levels. Similar results were obtained during the exploration of the two-microarray dataset.

CONCLUSIONS

This study suggests that CHI3L1 and CHI3L2 are associated with the progression of neurodegeneration in motor cortex and spinal cord of sALS patients.

Modelling C9orf72 dipeptide repeat proteins of a physiologically relevant size

C9orf72 expansions are the most common genetic cause of FTLD and MND identified to date. Although being intronic, the expansion is translated into five different dipeptide repeat proteins (DPRs) that accumulate within patients' neurons. Attempts have been made to model DPRs in cell and animals. However, the majority of these use DPRs repeat numbers much shorter than those observed in patients. To address this we have generated a selection of DPR expression constructs with repeat numbers in excess of 1000 repeats, matching what is seen in patients. Small and larger DPRs produce inclusions with similar morphology but different cellular effects. We demonstrate a length dependent effect using electrophysiology with a phenotype only occurring with the longest DPRs. These data highlight the importance of using physiologically relevant repeat numbers when modelling DPRs.

Low level of swiprosin-1/EFhd2 in vestibular nuclei of spontaneously hypersensitive motion sickness mice

Susceptibility to motion sickness (MS) varies considerably among humans. However, the cause of such variation is unclear. Here, we used a classical genetic approach to obtain mouse strains highly sensitive and resistant to MS (SMS and RMS). Proteomics analysis revealed substantially lower swiprosin-1 expression in SMS mouse brains. Inducing MS via rotary stimulation decreased swiprosin-1 in the mouse brains. Swiprosin-1 knockout mice were much more sensitive to motion disturbance. Immunohistochemistry revealed strong swiprosin-1 expression in the vestibular nuclei (VN). Over-expressing swiprosin-1 in the VN of SMS mice decreased MS susceptibility. Down-regulating swiprosin-1 in the VN of RMS mice by RNAi increased MS susceptibility. Additional in vivo experiments revealed decreased swiprosin-1 expression by glutamate via the NMDA receptor. Glutamate increased neuronal excitability in SMS or swiprosin-1 knockout mice more prominently than in RMS or wild-type mice. These results indicate that swiprosin-1 in the VN is a critical determinant of the susceptibility to MS.