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BITS PilaniHyderabad Campus
Vitamin D intake enhances Vitamin D
receptor expression in the striatum and
rescues memory and motor dysfunction in mouse model Huntington’s Disease
Presented by: S K Venkata Manjari1
Authors: S K Venkata Manjari1, P G Satwik1, Sanjana Srinivas2 and Pragya Komal1
1. Department of Biological Sciences, Birla Institute of Technology and Sciences –Pilani, Hyderabad, Telangana, India – 5000782. Department of Biotechnology, PES University, Bengaluru, Karnataka, India -560085
BITS Pilani, Hyderabad CampusBITS Pilani, Hyderabad Campus
ABSTRACTINTRODUCTION
A coordinated neuronal network between cortex and the basal ganglia is required for normal motor function, which gets severely impairedin Huntington’s disease (HD). In particular, the selective loss of medium spiny neurons in the striatum is considered as a prime brainregion responsible for movement disability observed in HD. In this regard, we explored the effect of high Vitamin D (VD) supplementationin HD animals which were induced with 3-nitropropionic acid (3-NP; 75mg/kg) as described previously (Fernagut et al., 2002).
METHODS
Male C57BL/6J mice (3-4 months old) were divided following groups: Vehicle (group I), 3-nitropropionic acid (HD induced group,intraperitoneal injection), only VD supplemented (group III, 500IU/kg) and 3-NP + VD supplementation (group IV). Animals were thensubjected to various behavioral tests like locomotion, gait analysis, Morris water maze (MWM) and rota-rod analysis. After 30 days,animals were decapitated and striatal tissues were isolated to check the mRNA expression of nerve growth factor (NGF), brain derivedneurotrophic factor (BDNF) and Vitamin D receptor (VDR).
RESULTS
Our behavior and mRNA data shows that VD intake significantly rescued striatal functions like motor co-ordination, locomotion andmemory known to be severely impaired in HD. Our results also indicate that VD mediated downstream neuroprotective pathomolecularpathway involves increase expression of Vitamin D receptor (VDR) and neurotrophic factors like NGF and BDNF in the striatum.
CONCLUSION
Altogether, we show that Vitamin D can be a potential “biodrug” to rescue neurodegeneration observed in HD via increased expression ofVDR and neurotrophic factors in the striatum.
KEYWORDS
Huntington’s disease (HD), Vitamin D (VD), Vitamin D receptor (VDR), Nerve growth factor (NGF), Brain-derived neurotrophic factor(BDNF).
REFERENCES
Fernagut, P. O. et al. Subacute systemic 3-nitropropionic acid intoxication induces a distinct motor disorder in adult C57Bl/6 mice:Behavioural and histopathological characterisation. Neuroscience 114, 1005–1017 (2002).
BITS Pilani, Hyderabad CampusBITS Pilani, Hyderabad Campus
INTRODUCTION & METHODOLOGY
Vitamin D Receptor
Healthy Neuron
Dying Neuron
VD Supplementati
on
NGF
Pre-synaptic cortical neuron
Post-synaptic striatal neuron
TrkBReceptor
BDNF
VD
ERK
CREB
Gene Expression Neurotroph
ic factors
TrkAReceptor
NGF
Cell Survival
BDNF
BDNF
NGFNGF
BDNF
Schematic Representation Hypothesizing the
Neuroprotective role of VD
3-NITROPROPIONIC ACID INDUCED MOUSE MODEL OF HUNTINGTON’S DISEASE:
3-nitropropionic acid (3-NP) is a neurotoxin that induces neuropathological symptoms that closely resembles that of HD. 3-NPleads to mitochondrial dysfunction in striatal neurons leading to neurodegeneration. 3-NP mouse model of HD can offer aunique system wherein testing of experimental treatments like vitamin D can be carried out to determine their neuroprotectiverole.
VITAMIN D AND NEUROPROTECTION
Vitamin D is an essential micronutrient which can be synthesized from cholesterol or can occur through dietary supplement. Inmost of the conditions neurodegeneration occurs due to hypovitaminosis D. In neurodegenerative disorders like Alzheimer’sand Parkinson’s disease, Vitamin D showed a rescue in cognitive impairment. Vitamin D supplementation shows itsneuroprotection via vitamin D receptor (VDR). Vitamin D shows its neuroprotective role by targeting other genes like nervegrowth factor (NGF) and brain-derived neurotrophic factor (BDNF) which mainly involves cell survival signal pathways.
Sample Text Column 1
HUNTINGTON'S DISEASE
Neurodegeneration involves a group of disorders characterized by the structural and functional loss of certain parts of centralnervous system. Huntington’s disease (HD) is a neurodegenerative disease principally characterized by neurodegeneration inthe striatum, which leads to the typical motor and cognitive impairments. Neurodegeneration is caused due to the increase inthe number of CAG (>40) repeats in Huntingtin gene located on 4th chromosome. Till date 7-10 in 1,00,000 were found inCaucasian population.The pathophysiology of HD arises both from cell autonomous processes within striatal neurons and dysfunction of inter-neuronal interactions, specifically at the level of the cortical-striatal afferents. The striatum serves as the information processinghub of the basal ganglia, integrating sensorimotor, cognitive, and motivation-related information. HD is characterized byalteration in the glutamatergic synaptic function in the striatum. It results in motor deficits that occur due to abnormalalternations in the cortico-striatal glutamatergic inputs to the MSNs.
METHODOLOGY
Animals were divided into four groups: Group I (Vehicle), Group II (3-NP or HD), Group III (control VD) and Group IV(HD+ VD). Animals were supplemented with 75mg/kg of 3-nitropropionic acid as per respective groups. Each group of animalswere undergone certain behavior to determine the rescue in motor dysfunction and memory in mouse model of Huntington’sdisease. Behavioral studies performed were as follows: a) Locomotor activity, b) Gait analysis, c) Rotarod analysis and d) Morriswatermaze test .Animals were decapitated after behavioral study . mRNA expression of the following genes were carried out to determine theneuroprotective role of vitamin D; namely 1. VDR, 2. NGF, and 3. BDNF.
Acclimat-ization
Day 0 Day 1 Day 2-15 Day 16-30RNA
Expression
Acclimatizing animalsAge: 11 weeks
VD treatment: 500IU/kgAge: 12 weeks Behavioral studies
Inducing with 3-NPAge: 12 weeks
VD treatment: 500IU/kgBehavioral studies
BITS Pilani, Hyderabad CampusBITS Pilani, Hyderabad Campus
Re
lati
ve
Q
ua
nti
ty o
f V
DR
*
VITAMIN D INCREASES mRNA EXPRESSION OF
VITAMIN D RECEPTOR IN THE STRIATUM
Effect of VD (500IU/kg) supplementation on expression
of VDR in 4 group of animals (a) Vehicle (b) 3-NP(c) VD and (d)
3-NP induced supplemented with VD; n=5, p=0.04, student’s t-test
RESULTS
Lo
co
mo
tio
n
No. of Days
****** *** ***
Vehicle HD VD HD+VD
VITAMIN D SUPPLEMENTATION RESCUED
NEUROMUSCULAR CO-ORDINATION IN
HD ANIMALS
VD (500IU/kg) supplementation shows no effect on stride length of forelimbs in 4 group of animals conducted via gait analysis VDsupplementation didn’t show effect in HD animals; n = 6, p=0.35; oneway anova
******E
sc
ap
e
La
ten
cy
(S
ec
.)
No. of Days
Vitamin D intake significantly increases grip strength suggestingincreased neuromuscular co-ordination as assessed by Rota-rodanalysis among 4 groups of animals. VD supplementationsignificantly rescued cognitive defcits observed in HD animalson 14th and 30th days; n = 4, p=0.009; student’s t-test
Vehicle HD VD HD+VD
No. of Days
La
ten
cy
of
Fir
st
Fa
ll
(Se
c.)
******
Re
lati
ve
Qu
an
tity
o
f N
GF
***
Re
lati
ve
Qu
an
tity
of
BD
NF
*
VDR - 110 bp
- 183 bpGAPDH - 88 bpNGF
- 92 bpBDNF
VITAMIN D SUPPLEMENTATION RESCUED
MOTOR DEFICITS IN HD ANIMALS
No. of Days
Str
ide
Le
ng
th
(cm
.)
Vehicle HD VD HD+VD
NO GAIT VARIABILITY OBSERVED IN HD ANIMALS
VITAMIN D RESCUED MEMORY DEFICITS IN HD ANIMALS
Spatial memory function conducted via morris water maze task from 4 groupof animals namely; (a) Vehicle (b) HD (c) VD and (d) VD + HD. VDsupplementation significantly rescued cognitive defcits observed in HDanimals on 20th and 30th days; n = 6, p=0.005; student’s t-test
VITAMIN D RECEPTOR MEDIATES STRIATAL
NEURONAL SURVIVAL VIA DOWNSTREAM
ACTIVATION OF NERVE GROWTH FACTOR
Effect of VD (500IU/kg) supplementation on expression
of NGF in 4 group of animals (a) Vehicle (b) 3-NP(c) VD and (d)
3-NP induced supplemented with VD; n=5, p=0.005, student’s t-
test
VITAMIN D RECEPTOR MEDIATES STRIATAL
NEURONAL SURVIVAL VIA DOWNSTREAM
ACTIVATION OF BRAIN DERIVED NEUROTROPHIC
FACTOR
Effect of VD (500IU/kg) supplementation on expression of BDNFin 4 group of animals (a) Vehicle (b) 3-NP(c) VD and (d) 3-NPinduced supplemented with VD; n=5, p=0.038, student’s t-test
VD (500IU/kg) supplementation significantly rescued movementdysfunction conducted via actophotometer among 4 group ofanimals. . VD supplementation significantly rescued cognitivedefcits observed in HD animals since 14th day; n = 6, p<0.001;one way Anova
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CONCLUSION
VITAMIN D IMPROVES MOVEMENT, MOTOR DYSFUNCTION AND MEMORY IN HUNTINGTON’S
DISEASE: The suggested dose of vitamin D supplementation in HD undertaken in our study shows that Vitamin D can significantly improve movement, motordysfunction, and memory. The possible neuroprotective downstream pathway operates via Vitamin D receptor induced increase in the expression ofneurotrophic factors like BDNF and NGF.
CONCLUSIONThe results of our work shows therapeutic benefit of Vitamin D supplementation in Huntington’s disease.
FOR MORE INFORMATION
If you are interested in more information about the work please contact:Dr. Pragya Komal, Assistant Professor,Department of Biological Sciences – Pilani,Hyderabad, Telangana, India - 500078
Email: [email protected]
REFERENCES
1)Barnhart et al. (2015) Using the morris water maze to assess spatial learning and memory in weanling mice. Plos One. 10:1-162)Copoccia et al. (2015) Behavioral characterization of mouse models of neuroferritinopathy. Plos One. 10:137-1523)Espindola et al. (2012) 3-nitropropionic acid modifies neurotrophin mRNA expression in the mouse striatum: 18S-rRNA is a reliable control gene for studies
of the striatum. Neurosci Bull. 28:517-5314)Gezen et al. (2014) The effect of vitamin D treatment on nerve growth factor (NGF) release from hippocampal neurons. Archives of Neuropsychiatry. 51:157-
1625)Kumar et al. (2009) Sesamol attenuate 3-nitropropionic acid-induce d huntington-like behavioral, biochemical, and cellular alterations in rats. J. Asian Nat.
Prod. Res. 11:439-4506)Mohamed et al. (2015) Neuroprotective role of vitamin D3 in colchicines-induced alzheimer’s disease in rats. Alexandria Journal of Medicine. 51:127-1367)Roze et al., (2011) Huntington’s disease and striatal signaling. frontiers of neuroanatomy. 11: 55-718)Yhnell et al. (2016) A longitudinal motor charachterization of the HdhQ111 mouse model of huntington’s disease. Journal of Huntington’s Disease. 5:149-161
ACKNOWLEDGEMENT
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