scholarly journals Neurogenesis in the adult Drosophila brain

Genetics ◽  
2021 ◽  
Author(s):  
Kassi L Crocker ◽  
Khailee Marischuk ◽  
Stacey A Rimkus ◽  
Hong Zhou ◽  
Jerry C P Yin ◽  
...  

Abstract Neurodegenerative diseases such as Alzheimer’s and Parkinson’s currently affect ∼25 million people worldwide (Erkkinen et al. 2018). The global incidence of traumatic brain injury (TBI) is estimated at ∼70 million/year (Dewan et al. 2018). Both neurodegenerative diseases and TBI remain without effective treatments. We are utilizing adult Drosophila melanogaster to investigate the mechanisms of brain regeneration with the long term goal of identifying targets for neural regenerative therapies. We specifically focused on neurogenesis, i.e. the generation of new cells, as opposed to the regrowth of specific subcellular structures such as axons. Like mammals, Drosophila have few proliferating cells in the adult brain. Nonetheless, within 24 hours of a Penetrating Traumatic Brain Injury (PTBI) to the central brain, there is a significant increase in the number of proliferating cells. We subsequently detect both new glia and new neurons and the formation of new axon tracts that target appropriate brain regions. Glial cells divide rapidly upon injury to give rise to new glial cells. Other cells near the injury site upregulate neural progenitor genes including asense and deadpan and later give rise to the new neurons. Locomotor abnormalities observed after PTBI are reversed within two weeks of injury, supporting the idea that there is functional recovery. Together, these data indicate that adult Drosophila brains are capable of neuronal repair. We anticipate that this paradigm will facilitate the dissection of the mechanisms of neural regeneration and that these processes will be relevant to human brain repair.

Author(s):  
Kassi L. Crocker ◽  
Khailee Marischuk ◽  
Stacey A. Rimkus ◽  
Hong Zhou ◽  
Jerry C.P. Yin ◽  
...  

AbstractUnderstanding the molecular and cellular mechanisms underlying neurogenesis after injury is crucial for developing tools for brain repair. We have established an adult Drosophila melanogaster model for investigating regeneration after central brain injury. Within 24 hours after Penetrating Traumatic Brain Injury (PTBI) to the central brain, we observe a significant increase in the number of proliferating cells. Between one- and two-weeks post-injury, we detect the generation of new neurons and glia and the formation of new axon tracts that target appropriate brain regions, suggesting there could be functional regeneration. Consistent with functional regeneration, locomotion abnormalities observed shortly after PTBI are largely reversed within 2 weeks of injury. Further, we find that cells surrounding the injury site upregulate neuroblast genes, such as asense and deadpan, and demonstrate that these cells give rise to the new neurons and glia. Taken together, our data support the hypothesis that young, adult Drosophila brains are capable of neuronal repair after central brain injury. We anticipate that our model will facilitate the dissection of the mechanisms of neural regeneration and anticipate that these processes will have relevance to humans.


2012 ◽  
Vol 33 (2) ◽  
pp. 311-318 ◽  
Author(s):  
Nicole A Terpolilli ◽  
Seong-Woong Kim ◽  
Serge C Thal ◽  
Wolfgang M Kuebler ◽  
Nikolaus Plesnila

Ischemia, especially pericontusional ischemia, is one of the leading causes of secondary brain damage after traumatic brain injury (TBI). So far efforts to improve cerebral blood flow (CBF) after TBI were not successful because of various reasons. We previously showed that nitric oxide (NO) applied by inhalation after experimental ischemic stroke is transported to the brain and induces vasodilatation in hypoxic brain regions, thus improving regional ischemia, thereby improving brain damage and neurological outcome. As regional ischemia in the traumatic penumbra is a key mechanism determining secondary posttraumatic brain damage, the aim of the current study was to evaluate the effect of NO inhalation after experimental TBI. NO inhalation significantly improved CBF and reduced intracranial pressure after TBI in male C57 Bl/6 mice. Long-term application (24 hours NO inhalation) resulted in reduced lesion volume, reduced brain edema formation and less blood–brain barrier disruption, as well as improved neurological function. No adverse effects, e.g., on cerebral auto-regulation, systemic blood pressure, or oxidative damage were observed. NO inhalation might therefore be a safe and effective treatment option for TBI patients.


Neurology ◽  
2018 ◽  
Vol 91 (15) ◽  
pp. 702-709 ◽  
Author(s):  
Stephanie M. Williams ◽  
Carrie Peltz ◽  
Kristine Yaffe ◽  
Philip Schulz ◽  
Michael R. Sierks

ObjectiveTo utilize a panel of 11 single chain variable fragments (scFvs) that selectively bind disease-related variants of TAR DNA-binding protein (TDP)-43, β-amyloid, tau, and α-synuclein to assess damage following traumatic brain injury (TBI), and determine if the presence of protein variants could account for the increased risk of various neurodegenerative diseases following TBI.MethodsWe utilized the panel of 11 scFvs in a sensitive ELISA format to analyze sera from 43 older veterans, 25 who had experienced at least 1 TBI incident during their lifetime (∼29.4 years after TBI), and 18 controls who did not incur TBI, in a cross-sectional study.ResultsEach of the 11 scFvs individually could significantly distinguish between TBI and control samples, though they did not detect each TBI sample. Comparing the levels of all 11 variants, all 25 TBI cases displayed higher reactivity compared to the controls and receiver operating characteristic analysis revealed 100% sensitivity and specificity. Higher total protein variants levels correlated with TBI severity and with loss of consciousness. Oligomeric tau levels distinguished between single and multiple TBI incidents. While all TBI cases were readily selected with the panel, the binding pattern varied from patient to patient, suggesting subgroups that are at increased risk for different neurodegenerative diseases.ConclusionThe panel of protein variants-specific scFvs can be used to identify blood-based biomarkers indicative of TBI even 20 years or more after the initial TBI. Being able to identify subgroups of biomarker profiles allows for the possibility of individually targeted treatments.


Neurotrauma ◽  
2018 ◽  
pp. 211-232
Author(s):  
Sarah C. Hellewell ◽  
Bridgette D. Semple ◽  
Jenna M. Ziebell ◽  
Nicole Bye ◽  
Cristina Morganti-Kossmann

Inflammation occurring following brain trauma represents a significant constituent of complex secondary responses that dictate patients’ outcome. Although a few decades have passed since its discovery, new aspects of this intriguing phenomenon are still being uncovered, ranging from the multiple roles of mediators regulating the inception, progression, and resolution of neuroinflammation, to the development of antiinflammatory therapies. This review provides a summary of the vast research on traumatic brain injury inflammation. The authors describe the fundamental aspects of cytokine and immune cell functions, the orchestrated collaboration of chemokines and leukocytes, the phenotypic distinction of macrophage populations, and the contribution of glial cells. Among the beneficial properties of neuroinflammation, they briefly discuss cytokines’ impact on neurogenesis; the chapter concludes by touching on the implications of antiinflammatory therapies.


ASN NEURO ◽  
2020 ◽  
Vol 12 ◽  
pp. 175909142093086
Author(s):  
Laura E. Montroull ◽  
Deborah E. Rothbard ◽  
Hur D. Kanal ◽  
Veera D’Mello ◽  
Vincent Dodson ◽  
...  

The p75 neurotrophin receptor (p75NTR) can regulate multiple cellular functions including proliferation, survival, and apoptotic cell death. The p75NTR is widely expressed in the developing brain and is downregulated as the nervous system matures, with only a few neuronal subpopulations retaining expression into adulthood. However, p75NTR expression is induced following damage to the adult brain, including after traumatic brain injury, which is a leading cause of mortality and disability worldwide. A major consequence of traumatic brain injury is the progressive neuronal loss that continues secondary to the initial trauma, which ultimately contributes to cognitive decline. Understanding mechanisms governing this progressive neuronal death is key to developing targeted therapeutic strategies to provide neuroprotection and salvage cognitive function. In this study, we demonstrate that a cortical impact injury to the sensorimotor cortex elicits p75NTR expression in apoptotic neurons in the injury penumbra, confirming previous studies. To establish whether preventing p75NTR induction or blocking the ligands would reduce the extent of secondary neuronal cell death, we used a noninvasive intranasal strategy to deliver either siRNA to block the induction of p75NTR, or function-blocking antibodies to the ligands pro-nerve growth factor and pro-brain-derived neurotrophic factor. We demonstrate that either preventing the induction of p75NTR or blocking the proneurotrophin ligands provides neuroprotection and preserves sensorimotor function.


2020 ◽  
pp. 1-12
Author(s):  
Cindy Santiago-Castañeda ◽  
Marysol Segovia-Oropeza ◽  
Luis Concha ◽  
Sandra Adela Orozco-Suárez ◽  
Luisa Rocha

Background: Severe traumatic brain injury (TBI), an important risk factor for Alzheimer’s disease, induces long-term hippocampal damage and hyperexcitability. On the other hand, studies support that propylparaben (PPB) induces hippocampal neuroprotection in neurodegenerative diseases. Objective: Experiments were designed to evaluate the effects of subchronic treatment with PPB on TBI-induced changes in the hippocampus of rats. Methods: Severe TBI was induced using the lateral fluid percussion model. Subsequently, rats received subchronic administration with PPB (178 mg/kg, TBI+PPB) or vehicle (TBI+PEG) daily for 5 days. The following changes were examined during the experimental procedure: sensorimotor dysfunction, changes in hippocampal excitability, as well as neuronal damage and volume. Results: TBI+PEG group showed sensorimotor dysfunction (p <  0.001), hyperexcitability (64.2%, p <  0.001), and low neuronal preservation ipsi- and contralateral to the trauma. Magnetic resonance imaging (MRI) analysis revealed lower volume (17.2%; p <  0.01) and great damage to the ipsilateral hippocampus. TBI+PPB group showed sensorimotor dysfunction that was partially reversed 30 days after trauma. This group showed hippocampal excitability and neuronal preservation similar to the control group. However, MRI analysis revealed lower hippocampal volume (p <  0.05) when compared with the control group. Conclusion: The present study confirms that post-TBI subchronic administration with PPB reduces the long-term consequences of trauma in the hippocampus. Implications of PPB as a neuroprotective strategy to prevent the development of Alzheimer’s disease as consequence of TBI are discussed.


2019 ◽  
Vol 43 (43) ◽  
pp. 17018-17022
Author(s):  
Baoping Zhai ◽  
Shuyang Zhai ◽  
Ruilin Hao ◽  
Jianjun Xu ◽  
Zhihong Liu

Traumatic brain injury (TBI) is a cause of neurodegenerative diseases accompanied by intracellular pH decrease. Herein, a FRET-based ratiometric two-photon fluorescent pH probe is designed to monitor pH change and understand TBI process.


2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Paul A. Taylor ◽  
Corey C. Ford

The objective of this modeling and simulation study was to establish the role of stress wave interactions in the genesis of traumatic brain injury (TBI) from exposure to explosive blast. A high resolution (1 mm3 voxels) five material model of the human head was created by segmentation of color cryosections from the Visible Human Female data set. Tissue material properties were assigned from literature values. The model was inserted into the shock physics wave code, CTH, and subjected to a simulated blast wave of 1.3 MPa (13 bars) peak pressure from anterior, posterior, and lateral directions. Three-dimensional plots of maximum pressure, volumetric tension, and deviatoric (shear) stress demonstrated significant differences related to the incident blast geometry. In particular, the calculations revealed focal brain regions of elevated pressure and deviatoric stress within the first 2 ms of blast exposure. Calculated maximum levels of 15 KPa deviatoric, 3.3 MPa pressure, and 0.8 MPa volumetric tension were observed before the onset of significant head accelerations. Over a 2 ms time course, the head model moved only 1 mm in response to the blast loading. Doubling the blast strength changed the resulting intracranial stress magnitudes but not their distribution. We conclude that stress localization, due to early-time wave interactions, may contribute to the development of multifocal axonal injury underlying TBI. We propose that a contribution to traumatic brain injury from blast exposure, and most likely blunt impact, can occur on a time scale shorter than previous model predictions and before the onset of linear or rotational accelerations traditionally associated with the development of TBI.


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