Stress-Related Neuronal Clusters in Sublenticular Extended Amygdala of Basal Forebrain Show Individual Differences of Positions

Kanemoto, Munenori; Nakamura, Tomoya; Sasahara, Masakiyo; Ichijo, Hiroyuki

doi:10.3389/fncir.2020.00029

Cited by 5 publications

(3 citation statements)

References 68 publications

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“…Similar altered subcellular localization of NeuN has also been reported in HIV-associated neurocognitive disorders [75]. Notably, we also found that Tdp-43 mislocalization markedly altered the localization and sequestration of murine NeuN in the cytosol of stressed and degenerative neurons (clustered) [76] in the inner layers (III-V) of the motor cortex and ventral horn of the thoracic spinal cord of mutant mice via an unknown mechanism. Further investigation is needed to test whether NeuN, an RNA splicing factor, interacts with TDP-43 directly within a spliceosome.…”

Section: Discussionsupporting

confidence: 87%

Endogenous TDP-43 mislocalization in a novel knock-in mouse model reveals DNA repair impairment, inflammation, and neuronal senescence

Mitra,

Dharmalingam,

Kodavati

et al. 2024

Preprint

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TDP-43 mislocalization and aggregation are key pathological features of motor neuron diseases (MND) including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, transgenic hTDP-43 WT or ∆NLS-overexpression animal models mainly capture late-stages TDP-43 proteinopathy, and do not provide a complete understanding of early motor neuron-specific pathology during pre-symptomatic phases. We have now addressed this shortcoming by generating a new endogenous knock-in (KI) mouse model using a combination of CRISPR/Cas9 and FLEX Cre-switch strategy for the conditional expression of a mislocalized Tdp-43∆NLS variant of mouse Tdp-43. This variant is either expressed conditionally in whole mice or specifically in the motor neurons. The mice exhibit loss of nuclear Tdp-43 concomitant with its cytosolic accumulation and aggregation in targeted cells, leading to increased DNA double-strand breaks (DSBs), signs of inflammation and DNA damage-associated cellular senescence. Notably, unlike WT Tdp43 which functionally interacts with Xrcc4 and DNA Ligase 4, the key DSB repair proteins in the non-homologous end-joining (NHEJ) pathway, the Tdp-43∆NLS mutant sequesters them into cytosolic aggregates, exacerbating neuronal damage in mice brain. The mutant mice also exhibit myogenic degeneration in limb muscles and distinct motor deficits, consistent with the characteristics of MND. Our findings reveal progressive degenerative mechanisms in motor neurons expressing endogenous Tdp-43∆NLS mutant, independent of TDP-43 overexpression or other confounding etiological factors. Thus, this unique Tdp-43 KI mouse model, which displays key molecular and phenotypic features of Tdp-43 proteinopathy, offers a significant opportunity to further characterize the early-stage progression of MND and also opens avenues for developing DNA repair-targeted approaches for treating TDP-43 pathology-linked neurodegenerative diseases.

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Section: Discussionsupporting

confidence: 87%

Endogenous TDP-43 mislocalization in a novel knock-in mouse model reveals DNA repair impairment, inflammation, and neuronal senescence

Mitra,

Dharmalingam,

Kodavati

et al. 2024

Preprint

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“…These results were consistent when compared to ISH maps from the Allan Brain Institute for Brain Science. Moreover, the BF is composed of various structures that include the extended amygdala (EA) and peripallidal regions, which facilitate processes of cortical activation motivation, attention, learning, and memory [ 23 , 32 , 33 ]. The BF is largely populated by cholinergic neurons compared to other neuronal cell types in rodents and primates, and these neurons project to the cerebral cortex, hippocampus, and amygdala [ 30 , 34 ].…”

Section: Discussionmentioning

confidence: 99%

Evaluation of eGFP expression in the ChAT-eGFP transgenic mouse brain

et al. 2023

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Background A historically definitive marker for cholinergic neurons is choline acetyltransferase (ChAT), a synthesizing enzyme for acetylcholine, (ACh), which can be found in high concentrations in cholinergic neurons, both in the central and peripheral nervous systems. ChAT, is produced in the body of the neuron, transported to the nerve terminal (where its concentration is highest), and catalyzes the transfer of an acetyl group from the coenzyme acetyl-CoA to choline, yielding ACh. The creation of bacterial artificial chromosome (BAC) transgenic mice that express promoter-specific fluorescent reporter proteins (green fluorescent protein—[GFP]) provided an enormous advantage for neuroscience. Both in vivo and in vitro experimental methods benefited from the transgenic visualization of cholinergic neurons. Mice were created by adding a BAC clone into the ChAT locus, in which enhanced GFP (eGFP) is inserted into exon 3 at the ChAT initiation codon, robustly and supposedly selectively expressing eGFP in all cholinergic neurons and fibers in the central and peripheral nervous systems as well as in non-neuronal cells. Methods This project systematically compared the exact distribution of the ChAT-eGFP expressing neurons in the brain with the expression of ChAT by immunohistochemistry using mapping and also made comparisons with in situ hybridization (ISH). Results We qualitatively described the distribution of ChAT-eGFP neurons in the mouse brain by comparing it with the distribution of immunoreactive neurons and ISH data, paying special attention to areas where the expression did not overlap, such as the cortex, striatum, thalamus and hypothalamus. We found a complete overlap between the transgenic expression of eGFP and the immunohistochemical staining in the areas of the cholinergic basal forebrain. However, in the cortex and hippocampus, we found small neurons that were only labeled with the antibody and not expressed eGFP or vice versa. Most importantly, we found no transgenic expression of eGFP in the lateral dorsal, ventral and dorsomedial tegmental nuclei cholinergic cells. Conclusion While the majority of the forebrain ChAT expression was aligned in the transgenic animals with immunohistochemistry, other areas of interest, such as the brainstem should be considered before choosing this particular transgenic mouse line.

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“…1C-D). Moreover, the BF is composed of various structures including the extended amygdala (EA) and peripallidal regions, facilitating processes of cortical activation motivation, attention, learning, and memory (Mesulam et al, 1983a;Masuda et al, 1997;Kanemoto et al, 2020). The BF is largely populated by cholinergic neurones compared to other neuronal cell types in rodents and primates, and these neurones project to the cerebral cortex, the hippocampus, and the amygdala (Gritti et al, 2003;Záborszky et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of eGFP expression in the ChAT-eGFP transgenic mouse brain

Gamage

Münch

Záborszky

et al. 2022

Preprint

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Background: A historically definitive marker for cholinergic neurons is choline acetyltransferase (ChAT), the synthesizing enzyme for acetylcholine, can be found in high concentration in cholinergic neurons, both in the central and peripheral nervous systems. ChAT, produced in the body of the neuron and is transported to the nerve terminal, where its concentration is highest, catalyzes the transfer of an acetyl group from the coenzyme acetyl-CoA to choline, yielding acetylcholine (Ach). The creation of the bacterial artificial chromosome (BAC) transgenic mice expressing promoter-specific fluorescent reporter proteins (green fluorescent protein - GFP) provided an enormous advantage for neuroscience. Both in vivo and in vitro experimental methods benefited from the transgenic visualization of the cholinergic neurons. Mice were created by adding a BAC clone into the ChAT locus, in which eGFP is inserted into exon 3 at the ChAT initiation codon, robustly and supposedly selectively expressing enhanced GFP (eGFP) in all cholinergic neurons and fibers in the central and peripheral nervous systems, as well as in non-neuronal cells. Methods: This project systematically compared the exact distribution of the ChAT-eGFP expressing neurons in the brain with the expression of ChAT by immunohistochemistry using mapping, and comparison with in situ hybridization (ISH). Results: We qualitatively described the distribution of ChAT-eGFP neurons in the mouse brain comparing it with the distribution of immunoreactive neurons and ISH data, paying special attention to areas where the expression is not overlapping, such as the cortex, the striatum, the thalamus and the hypothalamus. We found complete overlap between the transgenic expression of eGFP and the immunohistochemical staining in the areas of the cholinergic basal forebrain. However, in the cortex and hippocampus we found small neurons that were only labelled with the antibody and not expressed eGFP or vice versa. Most importantly, we found no transgenic expression of eGFP in the lateral dorsal, ventral and dorsomedial tegmental nuclei cholinergic cells. Conclusion: While the majority of the forebrain choline acetyltransferase expression was aligned in the transgenic animals with immunohistochemistry, other areas of interest, such as the brainstem should be considered before choosing this particular transgenic mouse line.

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Stress-Related Neuronal Clusters in Sublenticular Extended Amygdala of Basal Forebrain Show Individual Differences of Positions

Cited by 5 publications

References 68 publications

Endogenous TDP-43 mislocalization in a novel knock-in mouse model reveals DNA repair impairment, inflammation, and neuronal senescence

Endogenous TDP-43 mislocalization in a novel knock-in mouse model reveals DNA repair impairment, inflammation, and neuronal senescence

Evaluation of eGFP expression in the ChAT-eGFP transgenic mouse brain

Evaluation of eGFP expression in the ChAT-eGFP transgenic mouse brain

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