scholarly journals Mfn2 Ablation in the Adult Mouse Hippocampus and Cortex Causes Neuronal Death

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 116 ◽  
Author(s):  
Song Han ◽  
Priya Nandy ◽  
Quillan Austria ◽  
Sandra L. Siedlak ◽  
Sandy Torres ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cortical Neurons ◽  
Hippocampal Neurons ◽  
Adult Mouse ◽  
Nuclear Antigen ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Mitochondrial Fragmentation ◽  
Knock Out ◽  
Aberrant Cell

It is believed that mitochondrial fragmentation cause mitochondrial dysfunction and neuronal deficits in Alzheimer’s disease. We recently reported that constitutive knockout of the mitochondria fusion protein mitofusin2 (Mfn2) in the mouse brain causes mitochondrial fragmentation and neurodegeneration in the hippocampus and cortex. Here, we utilize an inducible mouse model to knock out Mfn2 (Mfn2 iKO) in adult mouse hippocampal and cortical neurons to avoid complications due to developmental changes. Electron microscopy shows the mitochondria become swollen with disorganized and degenerated cristae, accompanied by increased oxidative damage 8 weeks after induction, yet the neurons appear normal at the light level. At later timepoints, increased astrocyte and microglia activation appear and nuclei become shrunken and pyknotic. Apoptosis (Terminal deoxynucleotidyl transferase dUTP nick end labeling, TUNEL) begins to occur at 9 weeks, and by 12 weeks, most hippocampal neurons are degenerated, confirmed by loss of NeuN. Prior to the loss of NeuN, aberrant cell-cycle events as marked by proliferating cell nuclear antigen (PCNA) and pHistone3 were evident in some Mfn2 iKO neurons but do not colocalize with TUNEL signals. Thus, this study demonstrated that Mfn2 ablation and mitochondrial fragmentation in adult neurons cause neurodegeneration through oxidative stress and neuroinflammation in vivo via both apoptosis and aberrant cell-cycle-event-dependent cell death pathways.

FKBP51 Modulates Hippocampal Size and Function in Post-translational Regulation of Parkin

2021 ◽  
Author(s):  
Bin Qiu ◽  
Zhaohui Zhong ◽  
Shawn Righter ◽  
Yuxue Xu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Translational Regulation ◽  
Disease Onset ◽  
Fold Increase ◽  
Knock Out ◽  
Fk506 Binding Protein ◽  
Protein Levels ◽  
And Function

Abstract FK506-binding protein 51 (encoded by Fkpb51) has been associated with stress-related mental illness. To identify its function, we studied the morphological consequences of Fkbp51 deletion. Artificial Intelligence-assist morphological analysis identified that Fkbp51 knock-out (KO) mice possess more elongated CA and DG but shorter in height in coronal section when compared to WT. Primary cultured Fkbp51 KO hippocampal neurons were shown to exhibit larger dendritic outgrowth than wild-type (WT) controls, pharmacological manipulation experiments suggest that this may occur through regulation of microtubule-associated protein. Both in vitro primary culture and in vivo labeling support that FKBP51 regulates microtubule-associated protein expression. Furthermore, in the absence of differences in mRNA expression, Fkbp51 KO hippocampus exhibited decreases in βIII-tubulin, MAP2, and Tau protein levels, but a greater than 2.5-fold increase in Parkin protein. Overexpression and knock-down FKBP51 demonstrated that FKBP51 negatively regulates Parkin in a dose-dependent and ubiquitin-mediated manner. These results indicate a potential novel post-translational regulatory of Parkin by FKBP51 and significance of their interaction on disease onset.

scholarly journals Autophagy is Activated In Vivo during Trimethyltin-Induced Apoptotic Neurodegeneration: A Study in the Rat Hippocampus

2019 ◽  
Vol 21 (1) ◽  
pp. 175 ◽  
Author(s):  
Sabrina Ceccariglia ◽  
Alessandra Alvino ◽  
Aurora Del Fà ◽  
Ornella Parolini ◽  
Fabrizio Michetti ◽  
...  
Keyword(s):  
Western Blotting ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Neuronal Degeneration ◽  
Neuronal Loss ◽  
Organotin Compound ◽  
Nuclear Antigen ◽  
Apoptotic Pathway

Trimethyltin (TMT) is an organotin compound known to produce significant and selective neuronal degeneration and reactive astrogliosis in the rodent central nervous system. Autophagy is the main cellular mechanism for degrading and recycling protein aggregates and damaged organelles, which in different stress conditions, such as starvation, generally improves cell survival. Autophagy is documented in several pathologic conditions, including neurodegenerative diseases. This study aimed to investigate the autophagy and apoptosis signaling pathways in hippocampal neurons of TMT-treated (Wistar) rats to explore molecular mechanisms involved in toxicant-induced neuronal injury. The microtubule-associated protein light chain (LC3, autophagosome marker) and sequestosome1 (SQSTM1/p62) (substrate of autophagy-mediated degradation) expressions were examined by Western blotting at different time points after intoxication. The results demonstrate that the LC3 II/I ratio significantly increased at 3 and 5 days, and that p62 levels significantly decreased at 7 and 14 days. Immunofluorescence images of LC3/neuronal nuclear antigen (NeuN) showed numerous strongly positive LC3 neurons throughout the hippocampus at 3 and 5 days. The terminal deoxynucleotidyltransferase dUTP nick end labeling (TUNEL) assay indicated an increase in apoptotic cells starting from 5 days after treatment. In order to clarify apoptotic pathway, immunofluorescence images of apoptosis-inducing factor (AIF)/NeuN did not show nuclear translocation of AIF in neurons. Increased expression of cleaved Caspase-3 was revealed at 5–14 days in all hippocampal regions by Western blotting and immunohistochemistry analyses. These data clearly demonstrate that TMT intoxication induces a marked increase in both autophagy and caspase-dependent apoptosis, and that autophagy occurring just before apoptosis could have a potential role in neuronal loss in this experimental model of neurodegeneration.

scholarly journals Cytoplasmic p21Cip1/WAF1 regulates neurite remodeling by inhibiting Rho-kinase activity

2002 ◽  
Vol 158 (2) ◽  
pp. 321-329 ◽  
Author(s):  
Hiroyuki Tanaka ◽  
Toshihide Yamashita ◽  
Minoru Asada ◽  
Shuki Mizutani ◽  
Hideki Yoshikawa ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Developmental Process ◽  
Ectopic Expression ◽  
Rho Kinase ◽  
Nuclear Antigen ◽  
Nih3t3 Cells ◽  
Localization Signal ◽  
Newborn Neurons

p21Cip1/WAF1 has cell cycle inhibitory activity by binding to and inhibiting both cyclin/Cdk kinases and proliferating cell nuclear antigen. Here we show that p21Cip1/WAF1 is induced in the cytoplasm during the course of differentiation of chick retinal precursor cells and N1E-115 cells. Ectopic expression of p21Cip1/WAF1 lacking the nuclear localization signal in N1E-115 cells and NIH3T3 cells affects the formation of actin structures, characteristic of inactivation of Rho. p21Cip1/WAF1 forms a complex with Rho-kinase and inhibits its activity in vitro and in vivo. Neurite outgrowth and branching from the hippocampal neurons are promoted if p21Cip1/WAF1 is expressed abundantly in the cytoplasm. These results suggest that cytoplasmic p21Cip1/WAF1 may contribute to the developmental process of the newborn neurons that extend axons and dendrites into target regions.

Expression of polo-like kinase (PLK) in the mouse placenta and ovary

1999 ◽  
Vol 11 (1) ◽  
pp. 31 ◽  
Author(s):  
Noriyuki Takai ◽  
Jun Yoshimatsu ◽  
Yoshihiro Nishida ◽  
Isao Miyakawa ◽  
Ryoji Hamanaka ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cellular Proliferation ◽  
Cultured Cells ◽  
Embryo Implantation ◽  
Cell Types ◽  
Nuclear Antigen ◽  
Ovarian Stroma ◽  
Mouse Placenta ◽  
Trophoblastic Tissue

The polo-like kinase (PLK) is a mammalian serine/threonine kinase involved in cell cycle regulation. Much evidence for the role of PLK in the cell cycle has come from studies of cultured cells; however, little is known about its function or even expression in vivo . The present study examined the features of PLK expression in the mouse placenta and ovary. Immunohistochemical studies showed that PLK is highly expressed in the basement membrane of the endometrial gland, in some endothelial cells, in endometrium after embryo implantation, in trophoblastic tissue invading the decidua, in the ovarian stroma and in some lutein bodies. In contrast, PLK was not detectable by immunohistochemistry in endometrial stroma before decidualization, in decidua, in trophoblastic tissue not invading the decidua or in ovarian follicles. PLK expression seemed to be correlated with the expression of proliferation cellular nuclear antigen (PCNA) in many placental and ovarian cells, reflecting a role in cellular proliferation. Nevertheless, in ovarian stroma and lutein bodies where PCNA was not expressed, PLK was strongly expressed. This finding indicates that PLK may have some post mitotic functions in certain specialized cell types.

Comparative analysis of the intracellular localization of c-Myc, c-Fos, and replicative proteins during cell cycle progression

1992 ◽  
Vol 12 (8) ◽  
pp. 3548-3555
Author(s):  
S Vriz ◽  
J M Lemaitre ◽  
M Leibovici ◽  
N Thierry ◽  
M Méchali
Keyword(s):  
Cell Cycle ◽  
Dna Polymerase ◽  
Intracellular Localization ◽  
Initial Step ◽  
Embryonic Cell ◽  
Nuclear Antigen ◽  
Serum Starvation ◽  
Dna Polymerase Alpha ◽  
Serum Stimulation

In eukaryotic cells, nucleus-cytoplasm exchanges play an important role in genomic regulation. We have analyzed the localization of four nuclear antigens in different growth conditions: two replicative proteins, DNA polymerase alpha and proliferating cell nuclear antigen (PCNA), and two oncogenic regulatory proteins, c-Myc and c-Fos. A kinetic study of subcellular localization of these proteins has been done. In cultures in which cells were sparse, these proteins were detected in the nucleus. When proliferation was stopped by the high density of culture cells or by serum starvation, these proteins left the nucleus for the cytoplasm with different kinetics. DNA polymerase alpha is the first protein to leave the nucleus, with the PCNA protein, c-Fos, and c-Myc leaving the nucleus later. In contrast, during serum stimulation c-Fos and c-Myc relocalize into the nucleus before the replicative proteins. We also noticed that in sparse cell cultures, 10% of the cells exhibit a perinuclear staining for the DNA polymerase alpha, PCNA, and c-Myc proteins but not for c-Fos. This peculiar staining was also observed as an initial step to nuclear localization after serum stimulation and in vivo in Xenopus embryos when the G1 phase is reintroduced in the embryonic cell cycle at the mid-blastula stage. We suggest that such staining could reflect specific structures involved in the initiation of the S phase.

scholarly journals Dynein activating adaptor BICD2 controls radial migration of upper-layer cortical neurons in vivo

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Lena Will ◽  
Sybren Portegies ◽  
Jasper van Schelt ◽  
Merel van Luyk ◽  
Dick Jaarsma ◽  
...  
Keyword(s):  
Cortical Neuron ◽  
Cortical Neurons ◽  
Cortical Development ◽  
Adaptor Protein ◽  
Cortical Plate ◽  
Neuron Migration ◽  
Knock Out ◽  
Radial Migration

Abstract For the proper organization of the six-layered mammalian neocortex it is required that neurons migrate radially from their place of birth towards their designated destination. The molecular machinery underlying this neuronal migration is still poorly understood. The dynein-adaptor protein BICD2 is associated with a spectrum of human neurological diseases, including malformations of cortical development. Previous studies have shown that knockdown of BICD2 interferes with interkinetic nuclear migration in radial glial progenitor cells, and that Bicd2-deficient mice display an altered laminar organization of the cerebellum and the neocortex. However, the precise in vivo role of BICD2 in neocortical development remains unclear. By comparing cell-type specific conditional Bicd2 knock-out mice, we found that radial migration in the cortex predominantly depends on BICD2 function in post-mitotic neurons. Neuron-specific Bicd2 cKO mice showed severely impaired radial migration of late-born upper-layer neurons. BICD2 depletion in cortical neurons interfered with proper Golgi organization, and neuronal maturation and survival of cortical plate neurons. Single-neuron labeling revealed a specific role of BICD2 in bipolar locomotion. Rescue experiments with wildtype and disease-related mutant BICD2 constructs revealed that a point-mutation in the RAB6/RANBP2-binding-domain, associated with cortical malformation in patients, fails to restore proper cortical neuron migration. Together, these findings demonstrate a novel, cell-intrinsic role of BICD2 in cortical neuron migration in vivo and provide new insights into BICD2-dependent dynein-mediated functions during cortical development.

scholarly journals Basic FGF, NGF, and IGFs Protect Hippocampal and Cortical Neurons against Iron-Induced Degeneration

1993 ◽  
Vol 13 (3) ◽  
pp. 378-388 ◽  
Author(s):  
Ying Zhang ◽  
Tohru Tatsuno ◽  
John M. Carney ◽  
Mark P. Mattson
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Cortical Neurons ◽  
Hippocampal Neurons ◽  
Neuronal Degeneration ◽  
Cell Damage ◽  
Oxygen Radical ◽  
Neuroprotective Effects ◽  
In Vivo Models

Iron is believed to contribute to the process of cell damage and death resulting from ischemic and traumatic insults by catalyzing the oxidation of protein and lipids. Exposure of cultured rat hippocampal neurons to iron (FeSO4) caused a dose-dependent reduction in neuronal survival, which was potentiated by ascorbate. Damage to neurons was associated with a significant level of oxygen radical in the culture medium. The iron chelator desferal prevented both the neuronal degeneration caused by FeSO4 and the production of oxygen radical, demonstrating that ionic iron was responsible for the cell damage. Iron neurotoxicity was associated with an elevation of [Ca2+]i and was attenuated by NMDA receptor antagonists. Since recent findings demonstrated neuroprotective effects of growth factors in cell culture and in vivo models of ischemia, we examined the effects of growth factors on iron-induced damage. Basic fibroblast growth factor (bFGF), nerve growth factor (NGF), and insulinlike growth factors (IGF-I and IGF-II) each protected neurons against iron-induced damage. Both rat hippocampal and human cortical neurons were protected by these growth factors. Taken together, the data suggest that the neuroprotective effects of growth factors against excitotoxic/ischemic insults may result, in part, from a prevention or attenuation of oxidative damage.

scholarly journals ORF73 of Herpesvirus Saimiri, a Viral Homolog of Kaposi's Sarcoma-Associated Herpesvirus, Modulates the Two Cellular Tumor Suppressor Proteins p53 and pRb

2004 ◽  
Vol 78 (19) ◽  
pp. 10336-10347 ◽  
Author(s):  
Sumit Borah ◽  
Subhash C. Verma ◽  
Erle S. Robertson
Keyword(s):  
Cell Cycle ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Herpesvirus Saimiri ◽  
Nuclear Antigen ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
P53 Inactivation

ABSTRACT All known DNA tumor viruses are known to target and inactivate two main cell cycle regulatory proteins, retinoblastoma protein (pRb) and p53. Inactivation of pRb promotes host cell cycle progression into S phase, and inactivation of p53 promotes cell immortalization. The DNA tumor virus Kaposi's sarcoma associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA) was shown to target and inactivate pRb as well as p53. In this report we provide evidence that these functions are conserved in the homologous protein encoded by the related gammaherpesvirus herpesvirus saimiri (HVS). ORF73, the HVS homologue of LANA, is shown to bind both p53 and pRb in vitro and in vivo, to colocalize with p53 in human T cells infected with HVS, and in cells overexpressing both ORF73 and p53, as well as to adversely influence pRB/E2F and p53 transcriptional regulation. The C terminus of LANA, the region most highly conserved in ORF73, is shown to be responsible for both pRb and p53 interactions, supporting the hypothesis that these functions are conserved in both homologues. Finally, the region of p53 targeted by LANA (and ORF73) maps to the domain required for tetramerization. However, preliminary cross-linking studies do not detect disruption of p53 tetramerization by either LANA or HVS-encoded ORF73, suggesting that p53 inactivation may be by a mechanism independent of tetramer disruption.

scholarly journals c-Jun NH2-terminal Kinase (JNK)-interacting Protein-3 (JIP3) Regulates Neuronal Axon Elongation in a Kinesin- and JNK-dependent Manner

2013 ◽  
Vol 288 (20) ◽  
pp. 14531-14543 ◽  
Author(s):  
Tao Sun ◽  
Nuo Yu ◽  
Lu-Kai Zhai ◽  
Na Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Neuronal Development ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Anterograde Transport ◽  
Interacting Protein ◽  
Axon Elongation

The development of neuronal polarity is essential for the establishment of the accurate patterning of neuronal circuits in the brain. However, little is known about the underlying molecular mechanisms that control rapid axon elongation during neuronal development. Here, we report that c-Jun NH2-terminal kinase (JNK)-interacting protein-3 (JIP3) is highly expressed at axon tips during the critical period for axon development. Using gain- and loss-of-function approaches, immunofluorescence analysis, and in utero electroporation, we find that JIP3 can enhance axon elongation in primary hippocampal neurons and cortical neurons in vivo. We further demonstrate that JIP3 promotes axon elongation in a kinesin- and JNK-dependent manner using several deletion mutants of JIP3. Next, we demonstrate that the successful transportation of JIP3 to axon tips by kinesin is a prerequisite for enhancing JNK phosphorylation in this area and therefore promotes axon elongation, constituting a novel mechanism for coupling JIP3 anterograde transport with JNK signaling at the distal axons and axon elongation. Finally, our immunofluorescence data suggest that the activation of JNK at axon tips facilitates axon elongation by modulating cofilin activity and actin filament dynamics. These findings may have important implications for our understanding of neuronal axon elongation during development.

Phyllanthus urinaria’s Inhibition of Human Osteosarcoma Xenografts Growth in Mice is Associated with Modulation of Mitochondrial Fission/Fusion Machinery

2016 ◽  
Vol 44 (07) ◽  
pp. 1507-1523 ◽  
Author(s):  
Sheng-Teng Huang ◽  
Chao-Chun Huang ◽  
Jer-Ming Sheen ◽  
Tsu-Kung Lin ◽  
Pei-Lin Liao ◽  
...  
Keyword(s):  
Dynamic Change ◽  
B Cell Lymphoma ◽  
Significant Inhibition ◽  
Nuclear Antigen ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Mitochondrial Dynamic ◽  
Ki 67 ◽  
Proliferation Markers ◽  
Human Osteosarcoma

Osteosarcoma is an aggressive bone cancer arising from primitive transformed cells of mesenchymal origin to form malignant osteoid. Phyllanthus urinaria [Formula: see text]P. urinaria[Formula: see text] is a widely used folk medicine in cancer treatment, however the mechanism of P. urinaria inhibited human osteosarcoma is unclear. The present study was aimed at investigating the antitumoral effects of an aqueous P. urinaria on human osteosarcoma in vivo and the related underlying mechanisms, mainly focusing on mitochondrial dynamic dysfunction. Our results showed that oral administration of P. urinaria to mice led to significant inhibition of tumor development without substantial changes to body weight or major organs. Histological examinations with H&E, Giemsa, and Masson trichrome stains confirmed inhibition of tumor growth by the P. urinaria treatment. Immunohistochemical staining of proliferation markers antigen KI-67 (Ki67) and proliferating cell nuclear antigen (PCNA), as well as a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay demonstrated a decrease of tumor proliferation and an increase of apoptosis, which was associated with the modulation of B-cell lymphoma 2 (Bcl-2) family activating the caspase cascade in the P. urinaria-treated mice. The neovascularization marker cluster of differentiation 31 (CD31) was inhibited in P. urinaria-treated xenografts, implicating the potential anti-angiogenic effect of P. urinaria. P. urinaria treatment resulted in a significant decrease in the mitochondrial fusion proteins, including mitofusin 1/2 (Mfn1/2) and optic atrophy type 1 (Opa1), as well as an increase in the fission protein dynamin-related protein 1 (Drp1). The results of this study suggest mitochondrial dysfunction is associated with dynamic change that is involved in the apoptosis and anti-angiogenesis elicited by P. urinaria.

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