Implication of folate deficiency in CYP2U1 loss of function

Hereditary spastic paraplegias are heterogeneous neurodegenerative disorders. Understanding of their pathogenic mechanisms remains sparse, and therapeutic options are lacking. We characterized a mouse model lacking the Cyp2u1 gene, loss of which is known to be involved in a complex form of these diseases in humans. We showed that this model partially recapitulated the clinical and biochemical phenotypes of patients. Using electron microscopy, lipidomic, and proteomic studies, we identified vitamin B2 as a substrate of the CYP2U1 enzyme, as well as coenzyme Q, neopterin, and IFN-α levels as putative biomarkers in mice and fluids obtained from the largest series of CYP2U1-mutated patients reported so far. We also confirmed brain calcifications as a potential biomarker in patients. Our results suggest that CYP2U1 deficiency disrupts mitochondrial function and impacts proper neurodevelopment, which could be prevented by folate supplementation in our mouse model, followed by a neurodegenerative process altering multiple neuronal and extraneuronal tissues.

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Altered Expression of Peroxiredoxins in Mouse Model of Progressive Myoclonus Epilepsy upon LPS-Induced Neuroinflammation

Antioxidants ◽

10.3390/antiox10030357 ◽

2021 ◽

Vol 10 (3) ◽

pp. 357

Author(s):

Mojca Trstenjak Prebanda ◽

Petra Matjan-Štefin ◽

Boris Turk ◽

Nataša Kopitar-Jerala

Keyword(s):

Mouse Model ◽

Redox Homeostasis ◽

Underlying Mechanism ◽

Loss Of Function ◽

Altered Expression ◽

Lps Challenge ◽

Progressive Myoclonus Epilepsy ◽

Myoclonus Epilepsy ◽

The Brain ◽

Deficient Mice

Stefin B (cystatin B) is an inhibitor of endo-lysosomal cysteine cathepsin, and the loss-of-function mutations in the stefin B gene were reported in patients with Unverricht–Lundborg disease (EPM1), a form of progressive myoclonus epilepsy. Stefin B-deficient mice, a mouse model of the disease, display key features of EPM1, including myoclonic seizures. Although the underlying mechanism is not yet completely clear, it was reported that the impaired redox homeostasis and inflammation in the brain contribute to the progression of the disease. In the present study, we investigated if lipopolysaccharide (LPS)-triggered neuroinflammation affected the protein levels of redox-sensitive proteins: thioredoxin (Trx1), thioredoxin reductase (TrxR), peroxiredoxins (Prxs) in brain and cerebella of stefin B-deficient mice. LPS challenge was found to result in a marked elevation of Trx1 and TrxR in the brain and cerebella of stefin B deficient mice, while Prx1 was upregulated only in cerebella after LPS challenge. Mitochondrial peroxiredoxin 3 (Prx3), was upregulated also in the cerebellar tissue lysates prepared from unchallenged stefin B deficient mice, while after LPS challenge Prx3 was upregulated in stefin B deficient brain and cerebella. Our results imply the role of oxidative stress in the progression of the disease.

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An inducible mouse model for skin cancer reveals distinct roles for gain-and loss-of-function p53 mutations

Yearbook of Dermatology and Dermatologic Surgery ◽

10.1016/s0093-3619(08)70918-3 ◽

2008 ◽

Vol 2008 ◽

pp. 309

Author(s):

B.H. Thiers

Keyword(s):

Skin Cancer ◽

Mouse Model ◽

P53 Mutations ◽

Loss Of Function ◽

Gain And Loss

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DIPG-68. ALPHA-THALASSEMIA X-LINKED MENTAL RETARDATION PROTEIN (ATRX) LOSS-OF-FUNCTION IN A MOUSE MODEL OF DIFFUSE INTRINSIC PONTINE GLIOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa222.111 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii300-iii300

Author(s):

Chen Shen ◽

David Picketts ◽

Oren Becher

Keyword(s):

Mouse Model ◽

Pediatric Brain Tumor ◽

High Grade Glioma ◽

Genetic Alterations ◽

Genetically Engineered ◽

Tumor Incidence ◽

Loss Of Function ◽

Nestin Expression ◽

Genetically Engineered Mouse Model ◽

Clinical Cases

Abstract Diffuse Intrinsic Potine Glioma (DIPG) is a rare pediatric brain tumor for which no cure or efficacious therapies exist. Previous discoveries have revealed that, DIPG harbors distinct genetic alterations, when compared with adult high-grade glioma (HGG) or even with non-DIPG pediatric HGGs. ATRX alteration is found in 9% of clinical cases of DIPG, and significantly overlaps with H3.3K27M mutation and p53 loss, the two most common genetic changes in DIPG, found in 80% and 77% clinical cases, respectively. Here we developed genetically engineered mouse model of brainstem glioma using the RCAS-Tv-a system by targeting PDGF-B overexpression, p53 loss, H3.3K27M mutation and ATRX loss-of function to Nestin-expression brainstem progenitor cells of the neonatal mouse. Specifically, we used Nestin-Tv-a; p53 floxed; ATRX heterozygous female and Nestin-Tv-a; p53 floxed; ATRX floxed male breeders, generated offsprings with ATRX loss of function (n=18), ATRX heterozygous females (n=6), and ATRX WT (n=10). Median survial of the three groups are 65 days, 88 days and 51 days, respectively. Also, ATRX null mice is lower in tumor incidence (44.4%), compared with ATRX WT (80%). We evaluated the pathological features of DIPG with or without ATRX alteration, RNA-seq is performed to identify differentially expressed genes between ATRX WT and loss-of-function. In conclution, this study generated the first genetically modified mouse model studying ATRX loss-of-function in DIPG, and suggested that ATRX loss-of-function in DIPG may slow down tumorigenesis and decrease tumor incidence.

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Loss of TBK1 activity leads to TDP-43 proteinopathy through lysosomal dysfunction in human motor neurons

10.1101/2021.10.11.464011 ◽

2021 ◽

Author(s):

Jin Hao ◽

Michael F Wells ◽

Gengle Niu ◽

Irune Guerra San Juan ◽

Francesco Limone ◽

...

Keyword(s):

Motor Neuron ◽

Neurodegenerative Disease ◽

Motor Neurons ◽

Inhibition Mechanism ◽

Loss Of Function ◽

Neurodegenerative Process ◽

Lysosomal Dysfunction ◽

Human Motor ◽

Lateral Sclerosis ◽

Lysosomal Acidification

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron loss accompanied by cytoplasmic localization of TDP-43 proteins and their insoluble accumulations. Haploinsufficiency of TBK1 has been found to associate with or cause ALS. However, the cell-autonomous mechanisms by which reduced TBK1 activity contributes to human motor neuron pathology remain elusive. Here, we generated a human cellular model harboring loss-of-function mutations of TBK1 by gene editing and found that TBK1 deficiency was sufficient to cause TDP-43 pathology in human motor neurons. In addition to its functions in autophagy, we found that TBK1 interacted with endosomes and was required for normal endosomal maturation and subsequent lysosomal acidification. Surprisingly, TDP-43 pathology resulted more from the dysfunctional endo-lysosomal pathway than the previously recognized autophagy inhibition mechanism. Restoring TBK1 levels ameliorated lysosomal dysfunction and TDP-43 pathology and maintained normal motor neuron homeostasis. Notably, using patient-derived motor neurons, we found that haploinsufficiency of TBK1 sensitized neurons to lysosomal stress, and chemical regulators of endosomal maturation rescued the neurodegenerative process. Together, our results revealed the mechanism of TBK1 in maintaining TDP-43 and motor neuron homeostasis and suggested that modulating endosomal maturation was able to rescue neurodegenerative disease phenotypes caused by TBK1 deficiency.

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Hypomorphic and hypermorphic mouse models of Fsip2 indicate its dosage-dependent roles in sperm tail and acrosome formation

Development ◽

10.1242/dev.199216 ◽

2021 ◽

Vol 148 (11) ◽

Author(s):

Xiang Fang ◽

Yaser Gamallat ◽

Zhiheng Chen ◽

Hanran Mai ◽

Pei Zhou ◽

...

Keyword(s):

Mouse Model ◽

Physical Interaction ◽

Loss Of Function ◽

Internal Fertilization ◽

Fibrous Sheath ◽

Altered Expression ◽

Sperm Tail ◽

Acrosomal Vesicle ◽

Truncating Mutation ◽

Acrosome Formation

ABSTRACT Loss-of-function mutations in multiple morphological abnormalities of the sperm flagella (MMAF)-associated genes lead to decreased sperm motility and impaired male fertility. As an MMAF gene, the function of fibrous sheath-interacting protein 2 (FSIP2) remains largely unknown. In this work, we identified a homozygous truncating mutation of FSIP2 in an infertile patient. Accordingly, we constructed a knock-in (KI) mouse model with this mutation. In parallel, we established an Fsip2 overexpression (OE) mouse model. Remarkably, KI mice presented with the typical MMAF phenotype, whereas OE mice showed no gross anomaly except for sperm tails with increased length. Single-cell RNA sequencing of the testes uncovered altered expression of genes related to sperm flagellum, acrosomal vesicle and spermatid development. We confirmed the expression of Fsip2 at the acrosome and the physical interaction of this gene with Acrv1, an acrosomal marker. Proteomic analysis of the testes revealed changes in proteins sited at the fibrous sheath, mitochondrial sheath and acrosomal vesicle. We also pinpointed the crucial motifs of Fsip2 that are evolutionarily conserved in species with internal fertilization. Thus, this work reveals the dosage-dependent roles of Fsip2 in sperm tail and acrosome formation.

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Inhibition of microRNA-29a alleviates hyperoxia-induced bronchopulmonary dysplasia in neonatal mice via upregulation of GAB1

Molecular Medicine ◽

10.1186/s10020-019-0127-9 ◽

2019 ◽

Vol 26 (1) ◽

Cited By ~ 5

Author(s):

Yu Hu ◽

Liang Xie ◽

Jing Yu ◽

Hongling Fu ◽

Dan Zhou ◽

...

Keyword(s):

Bronchopulmonary Dysplasia ◽

In Silico Analysis ◽

Alveolar Epithelial Cells ◽

Loss Of Function ◽

Promote Cell Proliferation ◽

Alveolar Epithelial ◽

Neonatal Mice ◽

Potential Biomarker ◽

Proliferation And Apoptosis ◽

Direct Target Gene

Abstract Background The main features of bronchopulmonary dysplasia (BPD) are alveolar simplification, pulmonary growth arrest, and abnormal lung function. Multiple studies have highlighted microRNA-29 (miR-29) as a potential biomarker for lung diseases and cancers. Upregulation of miR-29a has been known to downregulate GRB2-associated-binding protein 1 (GAB1), which is often highly expressed in the lung. The current study was designed to investigate the potential role of miR-29a in hyperoxia-induced BPD by targeting GAB1 in a neonatal mouse model. Methods The expression of miR-29a and GAB1 in lung tissues of neonatal mice with hyperoxia-induced BPD and mouse alveolar epithelial cells (MLE-12) was determined using RT-qPCR and western blot analysis. Subsequently, the relationship between miR-29a and GAB1 was verified using in silico analysis. In order to assess the effects of miR-29a or GAB1 on BPD, the pathological characteristics of alveoli, as well as proliferation and apoptosis of cells were measured through gain- and loss-of-function studies. Results Upregulation of miR-29a and downregulation of GAB1 were evident in both lung tissues and MLE-12 cells following BPD modeling. GAB1 was a direct target gene of miR-29a. Inhibition of miR-29a and overexpression of GAB1 were shown to alleviate lung injury, promote cell proliferation and inhibit apoptosis but reduce chord length in lung tissues of neonatal mice following hyperoxia-induced BPD modeling. Conclusion Altogether, down-regulation of miR-29a can potentially elevate GAB1 expression, reducing cell apoptosis and stimulating proliferation, ultimately retarding the development of BPD in mice. This study highlights the potential of a promising new target for preventing BPD.

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Lactobacillus probiotics improved the gut microbiota profile of a Drosophila melanogaster Alzheimer’s disease model and alleviated neurodegeneration in the eye

Beneficial Microbes ◽

10.3920/bm2019.0086 ◽

2020 ◽

Vol 11 (1) ◽

pp. 79-89 ◽

Cited By ~ 2

Author(s):

F.H.P. Tan ◽

G. Liu ◽

S.-Y.A. Lau ◽

M.H. Jaafar ◽

Y.-H. Park ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Drosophila Melanogaster ◽

Gut Microbiota ◽

Neurodegenerative Disorders ◽

Dietary Intervention ◽

Disease Model ◽

Brain Health ◽

Potential Biomarker ◽

Microbiota Diversity

Alzheimer’s disease (AD) is a progressive disease and one of the most common forms of neurodegenerative disorders. Emerging evidence is supporting the use of various strategies that modulate gut microbiota to exert neurological and psychological changes. This includes the utilisation of probiotics as a natural and dietary intervention for brain health. Here, we showed the potential AD-reversal effects of Lactobacillus probiotics through feeding to our Drosophila melanogaster AD model. The administration of Lactobacillus strains was able to rescue the rough eye phenotype (REP) seen in AD-induced Drosophila, with a more prominent effect observed upon the administration of Lactobacillus plantarum DR7 (DR7). Furthermore, we analysed the gut microbiota of the AD-induced Drosophila and found elevated levels of Wolbachia. The administration of DR7 restored the gut microbiota diversity of AD-induced Drosophila with a significant reduction in Wolbachia’s relative abundance, accompanied by an increase of Stenotrophomonas and Acetobacter. Through functional predictive analyses, Wolbachia was predicted to be positively correlated with neurodegenerative disorders, such as Parkinson’s, Huntington’s and Alzheimer’s diseases, while Stenotrophomonas was negatively correlated with these neurodegenerative disorders. Altogether, our data exhibited DR7’s ability to ameliorate the AD effects in our AD-induced Drosophila. Thus, we propose that Wolbachia be used as a potential biomarker for AD.

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Mesenchymal stem cell-derived exosomal microRNA-136-5p inhibits chondrocyte degeneration in traumatic osteoarthritis by targeting ELF3

Arthritis Research & Therapy ◽

10.1186/s13075-020-02325-6 ◽

2020 ◽

Vol 22 (1) ◽

Author(s):

Xue Chen ◽

Yuanyuan Shi ◽

Pan Xue ◽

Xinli Ma ◽

Junfeng Li ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Mouse Model ◽

Cartilage Degeneration ◽

Clinical Samples ◽

Loss Of Function ◽

Post Traumatic ◽

Chondrocyte Migration

Abstract Background Emerging evidence suggests that microRNAs (miRs) are associated with the progression of osteoarthritis (OA). In this study, the role of exosomal miR-136-5p derived from mesenchymal stem cells (MSCs) in OA progression is investigated and the potential therapeutic mechanism explored. Methods Bone marrow mesenchymal stem cells (BMMSCs) and their exosomes were isolated from patients and identified. The endocytosis of chondrocytes and the effects of exosome miR-136-5p on cartilage degradation were observed and examined by immunofluorescence and cartilage staining. Then, the targeting relationship between miR-136-5p and E74-like factor 3 (ELF3) was analyzed by dual-luciferase report assay. Based on gain- or loss-of-function experiments, the effects of exosomes and exosomal miR-136-5p on chondrocyte migration were examined by EdU and Transwell assay. Finally, a mouse model of post-traumatic OA was developed to evaluate effects of miR-136-5p on chondrocyte degeneration in vivo. Results In the clinical samples of traumatic OA cartilage tissues, we detected increased ELF3 expression, and reduced miR-136-5p expression was determined. The BMMSC-derived exosomes showed an enriched level of miR-136-5p, which could be internalized by chondrocytes. The migration of chondrocyte was promoted by miR-136-5p, while collagen II, aggrecan, and SOX9 expression was increased and MMP-13 expression was reduced. miR-136-5p was verified to target ELF3 and could downregulate its expression. Moreover, the expression of ELF3 was reduced in chondrocytes after internalization of exosomes. In the mouse model of post-traumatic OA, exosomal miR-136-5p was found to reduce the degeneration of cartilage extracellular matrix. Conclusion These data provide evidence that BMMSC-derived exosomal miR-136-5p could promote chondrocyte migration in vitro and inhibit cartilage degeneration in vivo, thereby inhibiting OA pathology, which highlighted the transfer of exosomal miR-136-5p as a promising therapeutic strategy for patients with OA.

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