Species: Rat
Genes: Park7 (DJ1)
Modification: Park7 (DJ1): Knock-Out
Disease Relevance: Parkinson's Disease
Strain Name: LE-Park7^em1sage; HsdSage:LE-Park7^em1Sage; formerly LEH-Park7^tm1sage
Genetic Background: Long Evans Hooded
Availability: Available through Inotiv. Cryopreserved. (Previously available through Horizon Discovery (formerly Sage Labs), Cat #TGRL4830)

Summary

This knockout (KO) rat model was created at SAGE Labs (acquired first by Horizon Discovery, then by Envigo, and most recently by Inotiv) in collaboration with the Michael J. Fox Foundation. The rat carries a disrupted Park7 gene, which encodes the protein DJ-1. Homozygous DJ-1 KO rats develop motor (e.g., gait, strength) impairments and loss of dopaminergic neurons in the substantia nigra; however, levels of striatal dopamine are high (Dave et al., 2014).

The Park7 gene was disrupted using zinc finger nuclease (ZFN) technology, in which targeted ZFN RNA was injected into fertilized eggs. ZFNs were engineered to bind to a recognition sequence in exon 5 of Park7 and cleave DNA. When the resulting break was repaired by non- homologous end joining, the result was a 9 bp deletion and a 1 bp insertion. The resulting frame shift produced a premature stop codon. DJ-1 mRNA was dramatically reduced in homozygous rats. Likewise, DJ-1 protein was undetectable by western blot.

Homozygous rats appear normal at birth. There was no increase in mortality up to 8 months of age. Although one study found no difference between KO and wild-type rat weights (Dave et al., 2014), others have reported that KO male rats are heavier (Yang et al., 2018, Kyser et al., 2019).

Motor behavior was assessed systematically at 4, 6, and 8 months of age in one study (Dave et al., 2014) and at 2, 4, 7, and 13 months of age in another characterization study (Kyser et al., 2019). Notably, DJ-1 KO rats show abnormalities in gait and strength, as well as in vocalizations and tongue movement.

In terms of ambulatory behavior, KO rats rear less frequently, (Dave et al., 2014; Kyser et al., 2019; Giangrasso et al., 2020); in one study, this deficit abated by 13 months of age (Kyser et al., 2019), while in another the deficit became more pronounced at 8 months versus 4 or 6 months of age (Giangrasso et al., 2020). In another study, there was no overall difference in rearing or total distance travelled from 2 to 10 months of age (Sanchez et al. 2022). Despite deficits in rearing in some studies, DJ-1 KO rats travelled distances equivalent to those travelled by wild-type counterparts in an open-field test at 4, 6, and 8 months of age in one study (Dave et al., 2014), and in another study, DJ-1 KO rats actually had a higher number of forelimb and hindlimb steps taken at 4, 7, and 13 months of age compared to wild-type controls (Kyser et al., 2019). Moreover, no differences between DJ-1 KO and wild-type rats in exploratory behaviour were observed in an open-field test (Chiu et al., 2013). In contrast, Horizon reported open-field mobility impairment in five of 15 rats at 8 months of age (Inotiv Model Information Sheet, Jan 2023).

At four 4 months of age, abnormal paw positioning and a shorter stride than wild-type rats was reported (Dave et al., 2014). In the Kyser et al. study, stride length was comparable to wild-type rats at 2 months of age, but was reduced at 13 months (Kyser et al., 2019). However, at 2 months of age, the maximum stride difference was smaller in DJ-1 KO rats compared to wild-type rats (Kyser et al., 2019). Reduced overall muscle tone was evident by 8 months of age, with a notable lack of strength in the hind-limb extensor (Dave et al., 2014).

Motor coordination remained largely intact in the initial characterization study. DJ-1 KO rats They performed normally on the accelerating Rotarod at all ages and did not exhibit tremors (Dave et al., 2014). In addition, no differences between DJ-1 KO and wild-type rats were observed with regard to dyskinesia or catalepsy (Chiu et al. , 2013). However, in another study, performance on the accelerating Rotarod was significantly impaired in DJ-1 KO rats compared to wild-type controls (of note, both groups in this study received intravenous phosphate-buffered saline as part of the study design; Chiu et al., 2013). Moreover, in a more recent study, fine motor deficits were observed on an isometric pull bar task (at 7 to 9 months of age) in DJ-1 KO compared to wild-type rats, indicating reduced fine motor coordination in the forelimbs (Sanchez et al., 2022). On tests using a tapered balance beam, Yang et al. reported that male KO rats were slower than controls, but had fewer foot slips (Yang et al., 2018), while Dave et al. reported comparable performances to wild-type rats (Dave et al., 2014). A different study used a ledged tapered balance beam assay, which minimizes masking of behavior deficits due to rats not being able to shift their weight to avoid slipping off the beam when there is no underlying ledge (Giangrasso et al., 2020). This test revealed that DJ-1 KO rats did indeed have impaired motor coordination in the hindlimbs, and this deficit was more pronounced at 6 and 8 months of age than at 4 months (Giangrasso et al., 2020).

In addition, on the adjusting step test, which measures postural stability, DJ-1 KO rats in the Kyser et al. study took more adjusting steps than wild-type rats at 4, 7, and 13 months of age, which may reflect the increased striatal dopamine in this model (Kyser et al., 2019).

Regarding grooming, in the Dave et al. characterization study, DJ-1 KO rats did not exhibit grooming deficits (Dave et al., 2014), but in Kyser et al., DJ-1 KO rats did groom less than wild-type rats at 4, 7, and 13 months of age (Kyser et al., 2019).

Non-motor testing has also been evaluated to assess a variety of sensory, cognitive, and affective outcomes in male DJ-1 KO rats (Kyser et al., 2019). Sensorimotor function was not affected in DJ-1 KO rats at 4, 7, or 13 months of age, as assessed by the adhesive removal test (Kyser et al., 2019). The buried pellet test, which measures olfactory detection, revealed that 16-month-old DJ-1 KO rats took less time to find the treat than wild-type controls, indicating they may have better olfaction (Kyser et al., 2019). Short-term object- and place-recognition memory was also assessed in DJ-1 KO rats via the novel object/place recognition test (Kyser et al., 2019). On the novel object preference test, DJ-1 KO rats preferred the novel object at 4.5 months of age, but not at 15 months (Kyser et al., 2019). On the novel place preference test, DJ-1 KO rats showed short-term memory abnormalities based on their preference for the stationary versus moved object at both 4.5 and 15 months of age (Kyser et al., 2019). Appetitive instrumental learning was also assessed in DJ-1 KO rats using a lever-pressing assay, and no significant differences were observed compared to wild-type rats at 4, 6, or 8 months of age, indicating that the devaluation procedure was not impaired in DJ-1 KO rats (Giangrasso et al., 2020).

On the forced swim test, which measures ability to cope with stress, 6-month-old DJ-1 KO rats spent more time immobile and were quicker to become immobile versus wild-type controls, indicating the presence of impaired coping strategies (Kyser et al., 2019). Testing DJ-1 KO rats on the elevated plus maze revealed no differences in anxiety-like behavior from wild-type rats at any age measured (4, 8, and 17 months) (Kyser et al., 2019). However, in a light-dark box assay, DJ-1 KO rats spent less time in the dark compartment than wild-type rats (at both 6 and 8 months of age), indicating KO rats had less anxiety-like behavior (Giangrasso et al., 2020). Finally, no signs of anhedonia, an inability to feel pleasure, were observed based on the sucrose preference test (measured at 9 months of age), but DJ-1 KO rats did have more sucrose intake than wild-type rats, pointing to potential neuroendocrine abnormalities (Kyser et al., 2019).

Male DJ-1 KO rats produced longer and more frequent ultrasonic vocalizations than wild-type rats, and the average intensity of their calls decreased with age compared to age-matched wild-type controls (Yang et al., 2018). In addition, they had a decreased ability to regulate tongue force during a licking task as early as 2 months of age.

Interestingly, DJ-1 KO rats had more dopamine in the striatum than wild-type rats. Levels were elevated two- to threefold at 8 months of age. Similarly, striatal serotonin levels were up twp to threefold. There were no significant differences in the overall rate of turnover for either transmitter (Dave et al., 2014). Quantitative autoradiography revealed a higher density of dopaminergic receptors in the striatum. At eight months of age, DJ-1 KO rats had higher densities of all three receptor subtypes (D1, D2, and D3). The density of the dopamine transporter was unchanged (Sun et al., 2013).

Despite higher dopamine levels in the striatum, DJ-1 KO rats exhibited age-related decreases in the number of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra and locus coeruleus. Specifically, compared with wild-type rats, there was a 25 percent reduction in the substantia nigra at 6 months and a more than 50 percent reduction at 8 months. In the locus coeruleus, the loss reached nearly 50 percent at 8 months (Yang et al., 2018). TH-immunoreactivity was unaffected in the ventral tegmental area and the striatum (Dave et al., 2014).

In another study, the number of TH-positive neurons in the substantia nigra also did not differ between DJ-1 KO and wild-type rats (Chiu et al., 2013). Nonetheless, DJ-1 KO rats had more apoptotic cells in the striatum (but not in the hippocampus) than wild-type controls, based on TUNEL staining and cell morphology (Chiu et al., 2013). In contrast to other studies, Giangrasso et al. found increases in TH staining in the dorsal striatum (medial and lateral), but only at 8 months of age and not 4 or 6 months of age in DJ-1 KO rats compared with wild-type rats (Giangrasso et al. 2020). Preprotachykinin mRNA, an indicator of postsynaptic dopaminergic neurotransmission, was also reduced in the dorsal striatum in DJ-1 KO rats versus wild-type controls at 4 months of age (Giangrasso et al. 2020). Finally, binding to the serotonin transporter in the prefrontal cortex was increased in DJ-1 KO rats compared to wild-type rats, particularly at earlier ages (4 months but not 6 or 8 months; Giangrasso et al. 2020).

Staining for α-synuclein revealed no increase in the striatum or in any other brain region assessed (Dave et al., 2014).

Dopaminergic innervation of the dorsal striatum (medial and lateral regions), as assessed by ligand binding to the dopamine transporter, was intact in DJ-1 KO rats at 4 and 6 months of age as compared to wild-type rats (Giangrasso et al., 2020).

Neurotransmitter release was assessed by in vivo microdialysis in the striatum of DJ-1 KO rats (Creed et al., 2019). Basal levels of neurotransmitters (dopamine, glutamate, acetylcholine) and dopamine metabolites (3,4-dihydroxyphenylacetic and homovanillic acid) were not different from wild-type rats at 4, 8, and 12 months of age (Creed et al., 2019). However, evoked release of glutamate was decreased at 8 months of age while evoked acetylcholine release was increased at 4 and 8 months of age compared to wild-type rats; no differences in evoked neurotransmitter release were observed at 12 months of age (Creed et al., 2019).

Mitochondrial function was examined by assessing the striatal nonsynaptic mitochondrial proteome and by a mitochondrial respiration assay in 3-month-old male DJ-1 KO rats (Stauch et al., 2016). A total of 25 mitochondrial proteins were found to exhibit differential expression in the nonsynaptic striatal samples from DJ-1 KO rats compared with Parkin and PINK1 KO rats (Stauch et al., 2016). Moreover, oxygen - consumption rate was increased in DJ-1 KO nonsynaptic striatal mitochondria, indicating perturbed mitochondrial respiration in this model (Stauch et al., 2016). These findings were similarly observed in synaptic samples. Proteomic analysis of synaptic mitochondria from 3‐month‐old DJ‐1 KO rats revealed differential expression of 76 mitochondrial proteins compared with wild-type controls (Almikhlafi et al., 2020). Mitochondrial respiration at the synapse was also increased in DJ‐1 KO rats versus wild-type rats, although no differences in electron flow were observed through different electron transport chain complexes (Almikhlafi et al., 2020). Another study found that hexokinase 1 was relocalized to the cytosol from the outer mitochondrial membrane in an age-dependent manner from brain samples of DJ-1 KO rats compared to wild-type rats (Hauser et al., 2017).

Phenotype Characterization

COMMENTS / QUESTIONS

No Available Comments

Make a comment or submit a question

To make a comment you must login or register.

References

Paper Citations

1. Dave KD, De Silva S, Sheth NP, Ramboz S, Beck MJ, Quang C, Switzer RC 3rd, Ahmad SO, Sunkin SM, Walker D, Cui X, Fisher DA, McCoy AM, Gamber K, Ding X, Goldberg MS, Benkovic SA, Haupt M, Baptista MA, Fiske BK, Sherer TB, Frasier MA. Phenotypic characterization of recessive gene knockout rat models of Parkinson's disease. Neurobiol Dis. 2014 Oct;70:190-203. Epub 2014 Jun 24 PubMed.
2. Yang KM, Blue KV, Mulholland HM, Kurup MP, Kelm-Nelson CA, Ciucci MR. Characterization of oromotor and limb motor dysfunction in the DJ1 -/- model of Parkinson disease. Behav Brain Res. 2018 Feb 26;339:47-56. Epub 2017 Nov 3 PubMed.
3. Kyser TL, Dourson AJ, McGuire JL, Hemmerle AM, Williams MT, Seroogy KB. Characterization of Motor and Non-Motor Behavioral Alterations in the Dj-1 (PARK7) Knockout Rat. J Mol Neurosci. 2019 Oct;69(2):298-311. Epub 2019 Jun 27 PubMed.
4. Giangrasso DM, Furlong TM, Keefe KA. Characterization of striatum-mediated behavior and neurochemistry in the DJ-1 knock-out rat model of Parkinson's disease. Neurobiol Dis. 2020 Feb;134:104673. Epub 2019 Nov 15 PubMed.
6. Chiu S, Terpstra KJ, Bureau Y, Hou J, Raheb H, Cernvosky Z, Badmeav V, Copen J, Husni M, Woodbury-Farina M. Liposomal-formulated curcumin [Lipocurc™] targeting HDAC (histone deacetylase) prevents apoptosis and improves motor deficits in Park 7 (DJ-1)-knockout rat model of Parkinson's disease: implications for epigenetics-based nanotechnology-driven drug platfor. J Complement Integr Med. 2013 Nov 7;10 PubMed.
7. Sun J, Kouranova E, Cui X, Mach RH, Xu J. Regulation of dopamine presynaptic markers and receptors in the striatum of DJ-1 and Pink1 knockout rats. Neurosci Lett. 2013 Oct 21; PubMed.
8. Creed RB, Menalled L, Casey B, Dave KD, Janssens HB, Veinbergs I, van der Hart M, Rassoulpour A, Goldberg MS. Basal and Evoked Neurotransmitter Levels in Parkin, DJ-1, PINK1 and LRRK2 Knockout Rat Striatum. Neuroscience. 2019 Jun 15;409:169-179. Epub 2019 Apr 25 PubMed.
9. Stauch KL, Villeneuve LM, Purnell PR, Pandey S, Guda C, Fox HS. SWATH-MS proteome profiling data comparison of DJ-1, Parkin, and PINK1 knockout rat striatal mitochondria. Data Brief. 2016 Dec;9:589-593. Epub 2016 Sep 23 PubMed.
11. Hauser DN, Mamais A, Conti MM, Primiani CT, Kumaran R, Dillman AA, Langston RG, Beilina A, Garcia JH, Diaz-Ruiz A, Bernier M, Fiesel FC, Hou X, Springer W, Li Y, de Cabo R, Cookson MR. Hexokinases link DJ-1 to the PINK1/parkin pathway. Mol Neurodegener. 2017 Sep 29;12(1):70. PubMed.

External Citations

1. Inotiv Model Information Sheet, Jan 2023
2. I

Further Reading

No Available Further Reading