Name: bioluminescence imaging of neuroinflammation in transgenic mice after peripheral inoculation of alpha-synuclein fibrils
Uploaded: 2017-04-13T13:00:00
Description: Watch this Scientific Journal Video about Bioluminescence Imaging of Neuroinflammation in Transgenic Mice After Peripheral Inoculation of Alpha-Synuclein Fibrils at JoVE.com

The authors thank Olga Sharma, Theresa Hundt, and the staff of the DZNE microscopy and animal facilities for technical support.

All procedures including animals were performed with approval of the animal protection committee of North Rhine-Westphalia State Environment Agency (LANUV). Animals were housed and cared for according to standard conditions with a 12 h light/dark cycle and free access to food and water.
1. Animal Model
<ol>
	<li>Intercross hemizygous Tg(Gfap-luc+/-) mice with hemizygous Tg(M83+/-) mice to generate hemizygous bigenic Tg(M83+/-:Gfap-luc+/...

<ol>
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Peripheral injection of alpha-synuclein fibrils into the peritoneum of Tg(M83+/-:Gfap-luc+/-) mice represents a facile method to induce neurologic disease accompanied by neuroinflammation to recapitulate important characteristics of synucleinopathies. Similarly, tongue injection represents another route for neuroinvasion by alpha-synuclein prionoids in transgenic mice but is less efficient. We chose to terminate our experiments at 420 days after injection and we cannot exclude the possibili...

There is growing evidence that alpha-synuclein has characteristics that are similar to those of the prion protein, particularly in its capacity to self-seed and propagate misfolding between cells and along neuronal pathways. This property of alpha-synuclein is also referred to as &#39;prion-like&#39; or &#39;prionoid&#39;, and is supported by observations in transplantation experiments, which suggest the transmissibility of misfolded alpha-synuclein from diseased neurons to newly transplanted healthy neurons1,2,3,4. Also direct injection of misfolded alpha-synuclein into the brain or the periphery, e.g. the hindlimb muscle or intestinal wall, results in a spread of alpha-synuclein pathology to distal parts of the CNS5,6,7,8,9,10. We analyzed transmission of alpha-synuclein prionoids via peripheral routes in more detail and addressed the question whether misfolded alpha-synuclein may neuroinvade the CNS after a single intraglossal or intraperitoneal injection, a feature that previously had been shown for prions but not for misfolded alpha-synuclein. After injection of prions into the tongue, neuroinvasion of the CNS is achieved via propagation along the hypoglossal nerve of the tongue that leads to the nucleus of the hypoglossal nerve, which is located in the brain stem11. As a mouse model we chose Tg(M83+/-:Gfap-luc+/-) mice that overexpress the A53T mutant of human alpha-synuclein from the prion promoter, and firefly luciferase under control of a Gfap promoter to monitor astrocytic activation by bioluminescence, as previously shown in the brain of prion-infected mice12. In our hands bigenic Tg(M83+/-:Gfap-luc+/-) mice did not develop disease until 23 months of age as has been shown by others13. A single injection of human alpha-synuclein fibrils via the intraglossal or intraperitoneal route induced neurologic disease with pathology in the brains and spinal cords of Tg(M83+/-:Gfap-luc+/-) mice supporting the hypothesis that alpha-synuclein prionoids share important characteristics with prions14.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>anti-actin antibody</td>
			<td>Merck Millipore</td>
			<td>MAB1501</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-alpha-synuclein, phospho S129 antibody [pSyn#64]</td>
			<td>Wako</td>
			<td>015-25191</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-alpha-synuclein, phospho S129 antibody [EP1536Y]</td>
			<td>Abcam</td>
			<td>ab51253</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-GFAP antibody</td>
			<td>Dako</td>
			<td>Z0334 01</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-IBA-1 antibody</td>
			<td>Wako</td>
			<td>019-19741</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-Sequestosome-1 (p62) antibody</td>
			<td>Proteintech</td>
			<td>18420-1-AP</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-ubiquitin antibody [Ubi-1]</td>
			<td>Merck Millipore</td>
			<td>MAB1510</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-buffered saline (PBS)</td>
			<td>Invitrogen</td>
			<td>14190169</td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamine&#160;</td>
			<td>Ratiopharm</td>
			<td></td>
			<td>100 mg/kg</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Ratiopharm</td>
			<td></td>
			<td>10 mg/kg</td>
		</tr>
		<tr>
			<td>27-gauge syringe</td>
			<td>VWR</td>
			<td>613-4900</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane&#160;</td>
			<td>Piramal Healthcare</td>
			<td>PZN&#160; 4831850</td>
			<td></td>
		</tr>
		<tr>
			<td>Depilatory cream</td>
			<td>Veet</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Secureline lab marker&#160;</td>
			<td>Neolab</td>
			<td>25040</td>
			<td></td>
		</tr>
		<tr>
			<td>D-luciferin potassium salt</td>
			<td>Acris</td>
			<td>LK10000</td>
			<td>30 mg/mL stock solution</td>
		</tr>
		<tr>
			<td>Thermomixer</td>
			<td>Eppendorf</td>
			<td>5776671</td>
			<td></td>
		</tr>
		<tr>
			<td>Sonopuls Mini20 sonicator</td>
			<td>Bandelin</td>
			<td>3648</td>
			<td></td>
		</tr>
		<tr>
			<td>IVIS Lumina II imaging system</td>
			<td>PerkinElmer</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Living Image 3.0 Software</td>
			<td>PerkinElmer</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tg(M83+/-) mice or B6;C3-Tg(Prnp-SNCA*A53T)83Vle/J mice</td>
			<td>The Jackson Laboratory</td>
			<td>004479</td>
			<td></td>
		</tr>
		<tr>
			<td>Standard pattern forceps</td>
			<td>Fine Science Tools</td>
			<td>11000-16</td>
			<td></td>
		</tr>
		<tr>
			<td>Narrow pattern forceps</td>
			<td>Fine Science Tools</td>
			<td>11002-12</td>
			<td></td>
		</tr>
		<tr>
			<td>N-laurylasarcosyl</td>
			<td>Sigma</td>
			<td>L5125-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Optima Max-XP ultracentrifuge&#160;</td>
			<td>Beckman Coulter</td>
			<td></td>
			<td>TLA-110 rotor&#160;</td>
		</tr>
		<tr>
			<td>Thickwall polycarbonate tubes</td>
			<td>Beckman Coulter</td>
			<td>362305</td>
			<td></td>
		</tr>
		<tr>
			<td>NuPAG Novex 4-12% Bis-Tris Midi Protein Gels</td>
			<td>Thermo Fisher Scientific</td>
			<td>WG1401BOX</td>
			<td></td>
		</tr>
		<tr>
			<td>HRP conjugated antibody</td>
			<td>Cayman</td>
			<td>Cay10004301-1</td>
			<td></td>
		</tr>
		<tr>
			<td>IR Dye 680 conjugated antibody&#160;</td>
			<td>LI-COR Biosciences</td>
			<td>926-68070</td>
			<td></td>
		</tr>
		<tr>
			<td>SuperSignal West Dura Extended Duration Substrate</td>
			<td>Thermo Fisher Scientific</td>
			<td>34075</td>
			<td></td>
		</tr>
		<tr>
			<td>Stella 3200 imaging system</td>
			<td>Raytest</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Odyssey infrared imaging system&#160;</td>
			<td>LI-COR Biosciences</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 20&#160;</td>
			<td>MP Biomedicals</td>
			<td>TWEEN201</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>SA/T8787</td>
			<td></td>
		</tr>
		<tr>
			<td>Immobilon-FL PVDF membrane</td>
			<td>Merck Millipore</td>
			<td>IPFL00010</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylol</td>
			<td>Sigma</td>
			<td>Roth</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen peroxide</td>
			<td>Sigma</td>
			<td>SA/00216763/000500</td>
			<td>working solution 3%</td>
		</tr>
		<tr>
			<td>Bovine serum albumine (BSA)&#160;</td>
			<td>Thermo Fisher Scientific</td>
			<td>A3294-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat serum</td>
			<td>Thermo Fisher Scientific</td>
			<td>PCN5000</td>
			<td></td>
		</tr>
		<tr>
			<td>4,6-diamidino-2-phenylindole (DAPI)</td>
			<td>Thermo Fisher Scientific</td>
			<td>D1306</td>
			<td>working dilution 1:50,000</td>
		</tr>
		<tr>
			<td>Fluoromount media&#160;</td>
			<td>Omnilab</td>
			<td>SA/F4680/000025</td>
			<td></td>
		</tr>
		<tr>
			<td>LSM700 confocal laser scanning microscope</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>HALT protease and phosphatase inhibitors</td>
			<td>Thermo Fisher Scientific&#160;</td>
			<td>10516495</td>
			<td></td>
		</tr>
		<tr>
			<td>Precellys 24-Dual homogenizer&#160;</td>
			<td>Peqlab</td>
			<td>91-PCS24D</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa Fluor 488 conjugated antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>A31619</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa Fluor 594 conjugated antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>A11005</td>
			<td></td>
		</tr>
		<tr>
			<td>Pierce&#160;BCA&#160;Protein&#160;Assay&#160;Kit</td>
			<td>Thermo Fisher Scientific</td>
			<td>10741395</td>
			<td></td>
		</tr>
		<tr>
			<td>Microtome RM2255</td>
			<td>Leica</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>LSM700 confocal laser scanning microscope</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

bioluminescence imaging of neuroinflammation in transgenic mice after peripheral inoculation of alpha-synuclein fibrils

To study the prion-like behavior of misfolded alpha-synuclein, mouse models are needed that allow fast and simple transmission of alpha-synuclein prionoids, which cause neuropathology within the central nervous system (CNS). Here we describe that intraglossal or intraperitoneal injection of alpha-synuclein fibrils into bigenic Tg(M83+/-:Gfap-luc+/-) mice, which overexpress human alpha-synuclein with the A53T mutation from the prion protein promoter and firefly luciferase from the promoter for glial fibrillary acidic protein (Gfap), is sufficient to induce neuropathologic disease. In comparison to homozygous Tg(M83+/+) mice that develop severe neurologic symptoms beginning at an age of 8 months, heterozygous Tg(M83+/-:Gfap-luc+/-) animals remain free of spontaneous disease until they reach an age of 22 months. Interestingly, injection of alpha-synuclein fibrils via the intraperitoneal route induced neurologic disease with paralysis in four of five Tg(M83+/-:Gfap-luc+/-) mice with a median incubation time of 229 &#177;17 days. Diseased animals showed severe deposits of phosphorylated alpha-synuclein in their brains and spinal cords. Accumulations of alpha-synuclein were sarkosyl-insoluble and colocalized with ubiquitin and p62, and were accompanied by an inflammatory response resulting in astrocytic gliosis and microgliosis. Surprisingly, inoculation of alpha-synuclein fibrils into the tongue was less effective in causing disease with only one of five injected animals showing alpha-synuclein pathology after 285 days. Our findings show that inoculation via the intraglossal route and more so via the intraperitoneal route is suitable to induce neurologic illness with relevant hallmarks of synucleinopathies in Tg(M83+/-:Gfap-luc+/-) mice. This provides a new model for studying prion-like pathogenesis induced by alpha-synuclein prionoids in greater detail.

Peripheral injection of alpha-synuclein prionoids via the tongue or the peritoneum induced neuropathology in the CNS of bigenic Tg(M83+/-:Gfap-luc+/-) mice (Table 1 and Figure 1). After a single intraperitoneal injection with alpha-synuclein fibrils, four of five mice developed neurologic disease with a median incubation time of 229 &#177;17 days. Surprisingly, only one of five mice developed CNS disease after intraglossal i...

Watch this Scientific Journal Video about Bioluminescence Imaging of Neuroinflammation in Transgenic Mice After Peripheral Inoculation of Alpha-Synuclein Fibrils at JoVE.com

Bioluminescence Imaging of Neuroinflammation in Transgenic Mice After Peripheral Inoculation of Alpha-Synuclein Fibrils

Peripheral injection of alpha-synuclein fibrils into the peritoneum or tongue of Tg(M83+/-:Gfap-luc+/-) mice, which express human alpha-synuclein with the familial A53T mutation and firefly luciferase, can induce neuropathology, including neuroinflammation, in their central nervous system.

To study the prion-like behavior of misfolded alpha-synuclein, mouse models are needed that allow fast and simple transmission of alpha-synuclein ...

The overall goal of this bioluminescence imaging method is to quantify neuroinflammation in the central nervous system of a Parkinson's disease mouse model after peripheral injection of alpha-synuclein fibrils. This method can help determine when and to what degree neuroinflammation occurs in mouse models of neurodegenerative diseases. The main advantage of this technique is the neuroinflammation can be noninvasively and repeatedly monitored until any mice develop neurologic illness.The implication of this technique is 10th hour diagnosis of neurological disease because an increase in bioluminescence due to nerve inflammation not only accompanies but often preceded neurological disease. Begin by properly anesthetizing the animal for surgery. Administer a toe-pinch and confirm that the animal does not withdraw the limb to indicate a surgical plane of anesthesia.Apply ophthalmic ointment to prevent dryness while under anesthesia. Use adhesive tape to carefully fix the animal onto a heating plate in a dorsal recumbent position with the head towards the investigator. Then fill a 27 gauge disposable hypodermic syringe with five microliters of sonicated alpha-synuclein fibrils.Next, use a pair of blunt nosed thumb forceps to hold the animal's mouth open and use the smaller pair of forceps to carefully pull out the tongue to make the underside of the tongue accessible for injection. Insert the needle of the syringe into the right or left bottom side of the tongue in proximity to the hypoglossal nerve. After five seconds, slowly inject the inoculum.Allow the needle to remain in place for a further five seconds to ensure that the inoculum penetrates the tissue, and then carefully withdraw the needle. After the injection, release the animal and allow it to remain on the heating plate under constant monitoring until complete recovery. For intraperitoneal injections, briefly narcotize the animals in an anesthesia chamber with isoflurane.Again, pinch the animal's toe and confirm that it does not withdraw its hindlimb to ensure proper anesthesia. Fill a 27 gauge disposable hypodermic syringe with 50 microliters of sonicated alpha-synucelin fibirls, or PBS. Hold the animal in a dorsal position with the head facing away from the investigator and downward at approximately 45 degrees.Directly inject into the peritoneum of the mouse without penetrating the small intestine or cecum located behind the abdominal wall. Monitor animals until they have recovered from the anesthesia. Prior to imaging, shave and depilate the heads of isoflurane anesthetized mice.Color the ears in black with a non-irritating marker to block unspecific bioluminescence. Weigh the animals prior to injection. Then calculate the exact volume of D-Luciferin for injection at 150 milligrams per kilogram of body weight.Intraperitoneally inject the calculated volume of D-Luciferin, and then return each animal to the anesthesia chamber. Start the imaging software. After the imaging system has reached its operating temperature, initialize the system by clicking on the Initialize button in the control panel.Then select the buttons Luminescent and Photograph. Set the exposure time to 60 seconds, the Binning to medium, the F/Stop to one, and the EM gain to off. Select Block and then Open.And then under the tab subject height, choose 1.50 from the dropdown menu. Ten minutes after injection with D-Luciferin, place the animals onto the heating plate in the imaging chamber, and ensure that their muscles are correctly placed in the anesthesia outlet. Switch the isoflurane flow from the inhalation chamber to the imaging chamber, and properly close the door of the imaging chamber.Click on the acquire button to measure the bioluminescence, which takes 60 seconds. Stop the isoflurane flow, and then return the animals to their cages. Use the imaging software to quantify bioluminescence by opening the tool palette menu and selecting ROI Tools.Under type, select Measurement ROI. Within ROI Tools, click the circle tool and select the number of ROIs to draw from the pull-down menu. Ideally three for three mice.In the image, right-click each ROI and under properties, adjust the width and height to 1.25 centimeters. Position each ROI over the brain area that is quantified. In the upper left of the image, set the units panel to radiance in photons.Then open the tool palette menu. Select image adjust and adjust the minimum and the maximum of the color scale. For instance, from 200, 000 to one million.Lastly, under file, click save to save the data. As shown here, after intraperitoneal injection with alpha-synuclein fibrils, four of the five A53T synuclein GFAP luciferous reporter transgenic mice developed neurologic disease within 229 days as indicated by the purple squares. However, only one of five interglossally injected mice developed neurologic illness within 285 days as indicated by the green circles.Bioluminescence imaging revealed that the transgenic mice emitted elevated bioluminescence from their brains and spinal cords, shortly before they developed signs of neurologic disease. This bioluminescence was more pronounced after intraperitoneal injection and absent after PBS injection suggesting an absence of astrocytic gliosis. This figure shows the bioluminescence in the brains of transgenic mice over time after intraperitoneal injection of alpha-synuclein fibrils.As shown by the blue, green, brown, and orange circles. Increased levels of bioluminescence above a threshold of 2 million photons per second per square centimeter per steradian were observed some weeks before these four individual mice developed neurologic signs of disease. One of five animals also showed elevated levels of bioluminescence shortly before it died 285 days after intraglossal injection with alpha-synuclein fibrils.In contrast, for healthy PBS injected control mice, and one animal that did not develop disease after intraperitoneal injection, with alpha-synuclein fibrils indicated by the red circles, the bioluminescence signal remained below threshold within the period of observation. Immunofluorescence staining of brain sections of diseased animals with antibodies against GFAP and Iba1 confirmed neuroinflammation with microgliosis and reactive astrocytes in regions with alpha-synuclein deposits. Healthy animals that did not accumulate deposits of alpha-synuclein showed little staining for GFAP and Iba1.Once mastered, this technique can be done in less than one hour if it's performed properly. After its development, this technique paved the way for researchers in the field of neurodegeneration to noninvasively explore neuroinflammation in the central nervous system of mice. After watching this video, you should have a good understanding of how to peripherally inject mice with alpha-synuclein fibrils and how to perform bioluminescence imaging to monitor CNS neuroinflammation.The overall goal of the procedure is to peripherally induce neurologic illness by intraglossal or intraperitoneal injection with alpha-synuclein fibrils and to noninvasively image the induction of neuroinflammation over time.

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Research

JoVE Journal

Neuroscience

A Thin-skull Window Technique for Chronic Two-photon In vivo Imaging of Murine Microglia in Models of Neuroinflammation

Traditionally in neuroscience, in vivo two photon imaging of the murine central nervous system has either involved the use of open-skull1,2 or thinned-skull 3 preparations. While the open-skull technique is very versatile, it is not optimal for studying microglia because it is invasive and can cause microglial activation. Even though the thinned-skull approach is minimally invasive, the repeated re-thinning of skull required for chronic imaging increases the risks of tissue injury and microglial activation and allows for a limited number of imaging sessions. Here we present a chronic thin-skull window method for monitoring murine microglia in vivo over an extended period of time using two-photon microscopy. We demonstrate how to prepare a stable, accessible, thinned-skull cortical window (TSCW) with an apposed glass coverslip that remains translucent over the course of three weeks of intermittent observation. This TSCW preparation is far more immunologically inert with respect to microglial activation than open craniotomy or repeated skull thinning and allows an arbitrary number of imaging sessions during a time period of weeks. We prepare TSCW in CX3CR1 GFP/+ mice 4 to visualize microglia with enhanced green fluorescent protein to &le;150 &mu;m beneath the pial surface. We also show that this preparation can be used in conjunction with stereotactic brain injections of the HIV-1 neurotoxic protein Tat, adjacent to the TSCW, which is capable of inducing durable microgliosis. Therefore, this method is extremely useful for examining changes in microglial morphology and motility over time in the living brain in models of HIV Associated Neurocognitive Disorder (HAND) and other neurodegenerative diseases with a neuroinflammatory component.

A Thin-skull Window Technique for Chronic Two-photon In vivo Imaging of Murine Microglia in Models of Neuroinflammation

We describe a method for repeatedly visualizing murine microglia and circulating monocytes in vivo over hours, days or weeks using transcranial two-photon microscopy. We demonstrate how to prepare a thinned-skull window that allows intermittent observation of quiescent microglia that can be activated by adjacent stereotactic injection of the HIV-1 regulatory protein Tat.

Traditionally in neuroscience, in vivo two photon imaging of the murine central nervous system has either involved the use of open-skull1,2 or ...

Oral Administration of Rotenone using a Gavage and Image Analysis of Alpha-synuclein Inclusions in the Enteric Nervous System

In Parkinson's disease (PD) patients, the associated pathology follows a characteristic pattern involving inter alia the enteric nervous system (ENS) 1,2, the olfactory bulb (OB), the dorsal motor nucleus of the vagus (DMV)3, the intermediolateral nucleus of the spinal cord 4 and the substantia nigra, providing the basis for the neuropathological staging of the disease4,5. The ENS and the OB are the most exposed nervous structures and the first ones to be affected. Interestingly, PD has been related to pesticide exposure6-8. Here we show in detail two methods used in our previous study 9. In order to analyze the effects of rotenone acting locally on the ENS, we administered rotenone using a gavage to one-year old C57/BL6 mice. Rotenone is a widely used pesticide that strongly inhibits mitochondrial Complex I 10. It is highly lipophylic and poorly absorbed in the gastrointestinal tract 11. Our results showed that the administration of 5 mg/kg of rotenone did not inhibit mitochondrial Complex I activity in the muscle or the brain. Thus, suggesting that using our administration method rotenone did not cross the hepatoportal system and was acting solely on the ENS. Here we show a method to administer pesticides using a gavage and the image analysis protocol used to analyze the effects of the pesticide in alpha-synuclein accumulation in the ENS. The first part shows a method that allows intragastric administration of pesticides (rotenone) at a desired precise concentration. The second method shows a semi-automatic image analysis protocol to analyze alpha-synuclein accumulation in the ENS using an image analysis software.

Parkinson's disease has been related to the exposure to pesticides. Here we show a method to deliver pesticides using a gastric tube at the desired concentration and a method to analyze their effect in alpha-synuclein accumulation in the enteric nervous system.

In Parkinson's disease (PD) patients, the associated pathology follows a characteristic pattern involving inter alia the enteric nervous system (ENS) 1,2, ...

Generation of Topically Transgenic Rats by In utero Electroporation and In vivo Bioluminescence Screening

In utero electroporation (IUE) is a technique which allows genetic modification of cells in the brain for investigating neuronal development. So far, the use of IUE for investigating behavior or neuropathology in the adult brain has been limited by insufficient methods for monitoring of IUE transfection success by non-invasive techniques in postnatal animals. 
 For the present study, E16 rats were used for IUE. After intraventricular injection of the nucleic acids into the embryos, positioning of the tweezer electrodes was critical for targeting either the developing cortex or the hippocampus. 
 Ventricular co-injection and electroporation of a luciferase gene allowed monitoring of the transfected cells postnatally after intraperitoneal luciferin injection in the anesthetized live P7 pup by in vivo bioluminescence, using an IVIS Spectrum device with 3D quantification software. 
 Area definition by bioluminescence could clearly differentiate between cortical and hippocampal electroporations and detect a signal longitudinally over time up to 5 weeks after birth. This imaging technique allowed us to select pups with a sufficient number of transfected cells assumed necessary for triggering biological effects and, subsequently, to perform behavioral investigations at 3 month of age. As an example, this study demonstrates that IUE with the human full length DISC1 gene into the rat cortex led to amphetamine hypersensitivity. Co-transfected GFP could be detected in neurons by post mortem fluorescence microscopy in cryosections indicating gene expression present at &ge;6 months after birth.
 We conclude that postnatal bioluminescence imaging allows evaluating the success of transient transfections with IUE in rats. Investigations on the influence of topical gene manipulations during neurodevelopment on the adult brain and its connectivity are greatly facilitated. For many scientific questions, this technique can supplement or even replace the use of transgenic rats and provide a novel technology for behavioral neuroscience.

Generation of Topically Transgenic Rats by In utero Electroporation and In vivo Bioluminescence Screening

Genes can be manipulated during development of the cortex or the hippocampus of the rat via in utero electroporation (IUE) at E16, to enable fast and targeted modifications in neuronal connectivity for later studies of behavior or neuropathology in adult animals. Postnatal in vivo imaging for control of IUE success is performed by bioluminescence of activating co-transfected luciferase.

 In utero electroporation (IUE) is a technique which allows genetic modification of cells in the brain for investigating neuronal development. So far, the ...

Transplantation of Olfactory Ensheathing Cells to Evaluate Functional Recovery after Peripheral Nerve Injury

Olfactory ensheathing cells (OECs) are neural crest cells which allow growth and regrowth of the primary olfactory neurons. Indeed, the primary olfactory system is characterized by its ability to give rise to new neurons even in adult animals. This particular ability is partly due to the presence of OECs which create a favorable microenvironment for neurogenesis. This property of OECs has been used for cellular transplantation such as in spinal cord injury models. Although the peripheral nervous system has a greater capacity to regenerate after nerve injury than the central nervous system, complete sections induce misrouting during axonal regrowth in particular after facial of laryngeal nerve transection. Specifically, full sectioning of the recurrent laryngeal nerve (RLN) induces aberrant axonal regrowth resulting in synkinesis of the vocal cords. In this specific model, we showed that OECs transplantation efficiently increases axonal regrowth.
OECs are constituted of several subpopulations present in both the olfactory mucosa (OM-OECs) and the olfactory bulbs (OB-OECs). We present here a model of cellular transplantation based on the use of these different subpopulations of OECs in a RLN injury model. Using this paradigm, primary cultures of OB-OECs and OM-OECs were transplanted in Matrigel after section and anastomosis of the RLN. Two months after surgery, we evaluated transplanted animals by complementary analyses based on videolaryngoscopy, electromyography (EMG), and histological studies. First, videolaryngoscopy allowed us to evaluate laryngeal functions, in particular muscular cocontractions phenomena. Then, EMG analyses demonstrated richness and synchronization of muscular activities. Finally, histological studies based on toluidine blue staining allowed the quantification of the number and profile of myelinated fibers.
All together, we describe here how to isolate, culture, identify and transplant OECs from OM and OB after RLN section-anastomosis and how to evaluate and analyze the efficiency of these transplanted cells on axonal regrowth and laryngeal functions.

Olfactory ensheathing cells (OECs) are neural crest cells which allow growth of the primary olfactory neurons. This specific property can be used for cellular transplantation. We present here a model of cellular transplantation based on the use of OECs in a laryngeal nerve injury model.

Olfactory ensheathing cells (OECs) are neural crest cells which allow growth and regrowth of the primary olfactory neurons. Indeed, the primary olfactory ...

Fluorescence and Bioluminescence Imaging of Subcellular Ca2+ in Aged Hippocampal Neurons

Susceptibility to neuron cell death associated to neurodegeneration and ischemia are exceedingly increased in the aged brain but mechanisms responsible are badly known. Excitotoxicity, a process believed to contribute to neuron damage induced by both insults, is mediated by activation of glutamate receptors that promotes Ca2+ influx and mitochondrial Ca2+ overload. A substantial change in intracellular Ca2+ homeostasis or remodeling of intracellular Ca2+ homeostasis may favor neuron damage in old neurons. For investigating Ca2+ remodeling in aging we have used live cell imaging in long-term cultures of rat hippocampal neurons that resemble in some aspects aged neurons in vivo. For this end, hippocampal cells are, in first place, freshly dispersed from new born rat hippocampi and plated on poli-D-lysine coated, glass coverslips. Then cultures are kept in controlled media for several days or several weeks for investigating young and old neurons, respectively. Second, cultured neurons are loaded with fura2 and subjected to measurements of cytosolic Ca2+ concentration using digital fluorescence ratio imaging. Third, cultured neurons are transfected with plasmids expressing a tandem of low-affinity aequorin and GFP targeted to mitochondria. After 24 hr, aequorin inside cells is reconstituted with coelenterazine and neurons are subjected to bioluminescence imaging for monitoring of mitochondrial Ca2+ concentration. This three-step procedure allows the monitoring of cytosolic and mitochondrial Ca2+ responses to relevant stimuli as for example the glutamate receptor agonist NMDA and compare whether these and other responses are influenced by aging. This procedure may yield new insights as to how aging influence cytosolic and mitochondrial Ca2+ responses to selected stimuli as well as the testing of selected drugs aimed at preventing neuron cell death in age-related diseases.

Fluorescence and Bioluminescence Imaging of Subcellular Ca2+ in Aged Hippocampal Neurons

Intracellular Ca2+ remodeling in aging may contribute to excitotoxicity and neuron damage, processes mediated by Ca2+ overload. We aimed at investigating Ca2+ remodeling in the aging brain using fluorescence and bioluminescence imaging of cytosolic and mitochondrial Ca2+ in long-term cultures of rat hippocampal neurons, a model of neuronal aging.

Susceptibility to neuron cell death associated to neurodegeneration and ischemia are exceedingly increased in the aged brain but mechanisms responsible ...

Sequential Extraction of Soluble and Insoluble Alpha-Synuclein from Parkinsonian Brains

Alpha-synuclein (&#945;-syn) protein is abundantly expressed mainly within neurons, and exists in a number of different forms - monomers, tetramers, oligomers and fibrils. During disease, &#945;-syn undergoes conformational changes to form oligomers and high molecular weight aggregates that tend to make the protein more insoluble. Abnormally aggregated &#945;-syn is a neuropathological feature of Parkinson&#39;s disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Biochemical characterization and analysis of insoluble &#945;-syn using buffers with increasing detergent strength and high-speed ultracentrifugation provides a powerful tool to determine the development of &#945;-syn pathology associated with disease progression. This protocol describes the isolation of increasingly insoluble/aggregated &#945;-syn from post-mortem human brain tissue. This methodology can be adapted with modifications to studies of normal and abnormal &#945;-syn biology in transgenic animal models harbouring different &#945;-syn mutations as well as in other neurodegenerative diseases that feature aberrant fibrillar deposits of proteins related to their respective pathologies.

Here, we present a protocol for the isolation of increasingly insoluble/aggregated alpha-synuclein (&#945;-syn) from post-mortem human brain tissue. Through the utilization of buffers with increasing detergent strength and high-speed ultracentrifugation techniques, the variable properties of &#945;-syn aggregation in diseased and non-diseased tissue can be examined.

Alpha-synuclein (&#945;-syn) protein is abundantly expressed mainly within neurons, and exists in a number of different forms - monomers, tetramers, ...

Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice

The mammalian brain exhibits marked symmetry across the sagittal plane. However, detailed description of neural dynamics in symmetric brain regions in adult mammalian animals remains elusive. In this study, we describe an experimental procedure for measuring calcium dynamics through dual optical windows above bilateral primary somatosensory corticies (S1) in Thy1-GCaMP6s transgenic mice using 2-photon (2P) microscopy. This method enables recordings and quantifications of neural activity in bilateral mouse brain regions one at a time in the same experiment for a prolonged period in vivo. Key aspects of this method, which can be completed within an hour, include minimally invasive surgery procedures for creating dual optical windows, and the use of 2P imaging. Although we only demonstrate the technique in the S1 area, the method can be applied to other regions of the living brain facilitating the elucidation of structural and functional complexities of brain neural networks.

Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice

We describe an experimental procedure for measuring neuronal activity through dual optical windows above bilateral primary somatosensory corticies (S1) in Thy1-GCaMP6s transgenic mice using 2-photon (2P) microscopy in vivo.

The mammalian brain exhibits marked symmetry across the sagittal plane. However, detailed description of neural dynamics in symmetric brain regions in ...

Exogenous Administration of Microsomes-associated Alpha-synuclein Aggregates to Primary Neurons As a Powerful Cell Model of Fibrils Formation

For years, the inability of replicating formation of insoluble alpha-synuclein (&#945;S) inclusions in cell cultures has been a great limitation in the study of &#945;S aggregation in Parkinson&#39;s Disease (PD). Recently, the development of new animal models through the exogenous inoculation of brain extracts from diseased &#945;S transgenic mice or PD patients has given new hopes to the possibility of creating more adequate cell models of &#945;S aggregation. Unfortunately, when it comes to cells in cultures, administration of raw brain extracts has not proven as successful as in mice and the source of choice of exogenous aggregates is still in vitro preformed &#945;S fibrils.
We have developed a method to induce the formation of intracellular &#945;S inclusions in primary neurons through the exogenous administration of native microsomes-associated &#945;S aggregates, a highly toxic &#945;S species isolated from diseased areas of transgenic mice. This fraction of &#945;S aggregates that is associated with the microsomes vesicles, is efficiently internalized and induces the formation of intracellular inclusions positive for aggregated and phosphorylated &#945;S. Compared to in vitro-preformed fibrils which are made from recombinant &#945;S, our method is faster and guarantees that the pathogenic seeding is made with authentic &#945;S aggregates extracted from diseased animal models of PD, mimicking more closely the type of inclusions obtained in vivo. As a result, availability of tissues rich in &#945;S inclusions is mandatory.
We believe that this method will provide a versatile cell-based model to study the microscopic aspects of &#945;S aggregation and the related cellular pathophysiology in vivo and will be a starting point for the creation of more accurate and sophisticated cell paradigm of PD.

The goal of this protocol is to provide a cell-based system that replicates the formation of alpha-synuclein aggregates in vivo. Intracellular alpha-synuclein inclusions are seeded in primary neurons by the internalization and propagation of exogenous administered native microsomes-associated alpha-synuclein aggregates isolated from diseased alpha-synuclein transgenic mice.

For years, the inability of replicating formation of insoluble alpha-synuclein (&#945;S) inclusions in cell cultures has been a great limitation in the ...

Targeting Alpha Synuclein Aggregates in Cutaneous Peripheral Nerve Fibers by Free-floating Immunofluorescence Assay

To date, for most neurodegenerative diseases only a post-mortem histopathological definitive diagnosis is available. For Parkinson&#39;s disease (PD), the diagnosis still relies only on clinical signs of motor involvement that appear later on in the disease course, when most of the dopaminergic neurons are already lost. Hence, there is a strong need for a biomarker that can identify patients at the beginning of disease or at the risk of developing it. Over the last few years, skin biopsy has proved to be an excellent research and diagnostic tool for peripheral nerve diseases such as small fiber neuropathy. Interestingly, a small fiber neuropathy and alpha synuclein (&#945;Syn) neural deposits have been shown by skin biopsy in PD patients. Indeed, skin biopsy has the great advantage of being an easily accessible, minimally invasive and painless procedure that allows the analysis of peripheral nervous tissue prone to the pathology. Moreover, the possibility of repeating the skin biopsy in the course of the follow-up of the same patient allows studying the longitudinal correlation with the disease progression. We set up a standardized reliable protocol to investigate the presence of &#945;Syn aggregates in skin nerve fibers of the PD patient. This protocol involves few short fixation steps, a cryotome sectioning and then a free-floating immunofluorescence double-staining with two specific antibodies: anti Protein Gene Product 9.5 (PGP9.5) to mark the cutaneous nerve fibers and anti 5G4 for detecting &#945;Syn aggregates. It is a versatile, sensitive and easy to perform protocol that can also be applied for targeting other proteins of interest in skin nerves. The ability to mark &#945;Syn aggregates is another step forward to the use of skin biopsy as a tool for establishing a pre-mortem histopathological diagnosis of PD.

Here, we present a protocol for a free-floating indirect immunofluorescence assay on skin biopsy sections that allows for the identification of disease specific conformation variants of alpha synuclein involved in Parkinson disease and multiple proteins of the peripheral nervous system.

To date, for most neurodegenerative diseases only a post-mortem histopathological definitive diagnosis is available. For Parkinson&#39;s disease (PD), the ...

Generation of Alpha-Synuclein Preformed Fibrils from Monomers and Use In Vivo

Use of the in vivo alpha-synuclein preformed fibril (&#945;-syn PFF) model of synucleinopathy is gaining popularity among researchers aiming to model Parkinson&#39;s disease synucleinopathy and nigrostriatal degeneration. The standardization of &#945;-syn PFF generation and in vivo application is critical in order to ensure consistent, robust &#945;-syn pathology. Here, we present a detailed protocol for the generation of fibrils from monomeric &#945;-syn, post-fibrilization quality control steps, and suggested parameters for successful neurosurgical injection of &#945;-syn PFFs into rats or mice. Starting with monomeric &#945;-syn, fibrilization occurs over a 7-day incubation period while shaking at optimal buffer conditions, concentration, and temperature. Post-fibrilization quality control is assessed by the presence of pelletable fibrils via sedimentation assay, the formation of amyloid conformation in the fibrils with a thioflavin T assay, and electron microscopic visualization of the fibrils. Whereas successful validation using these assays is necessary for success, they are not sufficient to guarantee PFFs will seed &#945;-syn inclusions in neurons, as such aggregation activity of each PFF batch should be tested in cell culture or in pilot animal cohorts. Prior to use, PFFs must be sonicated under precisely standardized conditions, followed by examination using electron microscopy or dynamic light scattering to confirm fibril lengths are within optimal size range, with an average length of 50 nm. PFFs can then be added to cell culture media or used in animals. Pathology detectable by immunostaining for phosphorylated &#945;-syn (psyn; serine 129) is apparent days or weeks later in cell culture and rodent models, respectively.&#160;

The goal of this article is to outline the steps required for the generation of fibrils from monomeric alpha-synuclein, subsequent quality control, and use of the preformed fibrils in vivo.

Use of the in vivo alpha-synuclein preformed fibril (&#945;-syn PFF) model of synucleinopathy is gaining popularity among researchers aiming to model ...