MicroRNA-30e regulates neuroinflammation in MPTP model of Parkinson’s disease by targeting Nlrp3
MicroRNA‑30e regulates neuroinflammation in MPTP model of Parkinson's disease by targeting Nlrp3
Dongsheng Li 0
Hongqi Yang 0
Jianjun Ma 0
Sha Luo 0
Siyuan Chen 0
Qi Gu 0
0 Department of Neurology, Henan Provincial People Hospital , No. 7 Weiwu Road, Jinshui District, Zhengzhou 450003, Henan , China
1 Dongsheng Li
Accumulating evidences suggest that neuroinflammation is a pathological hallmark of Parkinson's disease (PD), a neurodegenerative disorder characterized by loss of dopaminergic neurons in substantia nigra pars compacta (SNpc). MicroRNAs have been recently recognized as crucial regulators of inflammatory responses. Here, we found significant downregulation of microRNA-30e (miR-30e) in SNpc of MPTP-induced PD mice. Next, we employed miR-30e agomir to upregulate miR30e expression in MPTP-treated mice. Our results showed that delivery of miR-30e agomir remarkably improved motor behavioral deficits and neuronal activity, and inhibited the loss of dopamine neurons. Moreover, the increased α-synuclein protein expression in SNpc of MPTP-PD mice was alleviated by the upregulation of miR-30e. Further, miR-30e agomir administration also attenuated the marked increase of inflammatory cytokines, such as TNF-α, COX-2, iNOS, and restored the decreased secretion of BDNF in SNpc. In addition, we demonstrated for the first time that miR-30e directly targeted to Nlrp3, thus suppressing Nlrp3 mRNA and protein expression. Finally, miR-30e upregulation significantly inhibited the activation of Nlrp3 inflammasome as evident from the decreased Nlrp3, Caspase-1 and ASC expressions and IL-18 and IL-1β secretions. Taken together, our study demonstrates that miR-30e ameliorates neuroinflammation in the MPTP model of PD by decreasing Nlrp3 inflammasome activity. These findings suggesting that miR30e may be a key inflammation-mediated molecule that could be a potential target for PD therapeutics.
Parkinson's disease; Neuroinflammation; Neurodegeneration; Nlrp3 inflammasome; miR-30e
Parkinson’s disease (PD) is the second only to Alzheimer’s
disease (AD) as the most common neurodegenerative
movement disorder, which is characterized with progressive loss
of dopaminergic neurons in the substantia nigra pars
compacta (SNpc) and accumulation of α-synuclein (α-syn) in
Lewy bodies [
]. The clinically used drugs, including
L-DOPA, monoamine oxidase type B inhibitors and
catechol-O-methyltransferase inhibitors, could only ameliorate
the symptoms through supplementing the absent dopamine,
but fail in delaying the process of dopamine neuronal
degeneration because it could not protect against neurons injury
]. Thus, developing a more effective agent remains the
top priority in prevention and treatment of PD.
Several lines of researches have suggested that
neuroinflammation is considered as the major central event in the
process of dopaminergic neuronal cell death in PD [
Enhanced levels of proinflammatory cytokines such as
TNFα, COX-2, IL-1β and IL-18 can be found in the analysis
of postmortem brain of PD patients [
]. Moreover, the
activity of IL-1β and IL-18 is critical controlled by a
cytoplasmic multiprotein, called “inflammasome”, which
contains nod-like receptor protein 3 (Nlrp3), adaptor protein
ASC and proinflammatory mediators Caspase-1, IL-18 and
IL-1β . Activation of Nlrp3 inflammasome has been
observed in a variety of neurodegenerative diseases,
including AD and amyotrophic lateral sclerosis (ALS) [
Importantly, Nlrp3 might be associated with the development of
PD and be a potential target for the treatment of PD [
However, the mechanisms underlying the regulation of
Nlrp3 inflammasome activity in PD are poorly understood.
Accumulating evidences indicate that post-transcriptional
regulation by microRNAs (miRs) is important for the
regulation of gene expression and inflammatory responses [
]. Sustained aberrant expression levels of several different
miRs have been described in inflammation-related
neurodegenerative disorders, including multiple sclerosis (MS), AD,
ALS and PD [
]. Therefore, identification of novel miR
machinery that modulates neuroinflammation not only helps
to understand the development of PD, but also provides a
new approach for the treatment of PD. In our study, we found
that exogenous delivery of miR-30e ameliorated neuronal
injury, neuroinflammaiton and dyskinesia in MPTP-induced
PD mice. Furthermore, miR-30e directly targeted to Nlrp3,
which in turn mediated Nlrp3 inflammsome activity and
Materials and methods
Materials and reagents
8-week-old male C57BL/6 mice were purchased from the
SLAC Laboratory (Shanghai, China) and were maintained
in cages with constant temperature (21 ± 1 °C), relative
humidity (60%), a strict 12 h/12 h light–dark cycle, and
free access to water and food. The experimental protocol
was approved by Institutional Animal Care and Use
Committee of Henan Provincial People Hospital and carried out
in accordance with the guidelines for the Care and Use of
MiR-30e agomir, miR-30e mimics, and corresponding
negative control miRNA were obtained from GenePharm
(Shanghai, China). SuperScriptIII First-Strand Synthesis
system, fetal bovine serum (FBS) Dulbecco’s modified
Eagle’s medium, penicillin, streptomycin and lipofectamine
2000 were purchased from Invitrogen (CA, USA).
Antibodies against α-syn, Nlrp3, ASC, Caspase-1 and β-actin were
from Cell Signaling Technology (MA, USA). Tyrosine
hydroxylase (TH) antibody, horseradish peroxidase
(HRP)conjugated goat anti-rabbit IgG antibody, HRP-donkey
antigoat IgG antibody and the Enhanced Chemiluminesecence
Kit were from Millipore (MA, USA). Nissl staining solution,
diaminobenzidine (DAB) and RIPA buffer were purchased
from Beyotime (Jiangsu, China). All chemicals and reagents
unless otherwise indicated were obtained from Sigma (MO,
Animal model and miR‑30e agomir delivery
The mice were received 3 times of intraperitoneally (i.p.)
injection of MPTP (20 mg/kg) at days 1, 7, and 14. Control
mice were administrated with saline only. Mice were killed
at different times after the first MPTP injection: 1, 3, 7, 10,
and 14 days. For the delivery of miR-30e in MPTP mice,
a stereotactic catheter was surgically implanted into the
right lateral ventricle of mice (Bregma: −2 mm, Lateral:
2 mm, Dorsoventral: 3 mm). 5 μL of saline containing
20 nmol/L of miR-30e agomir or a scramble sequence
control miRNA (negative control) was injected through the
catheter per day for 7 consecutive days. The first treatment
of agomir was performed 2 h after the last injection of
MPTP. The schematic diagram of miR-30e administration
is illustrated in Figure S1. Mice were killed immediately
after behavioral assessments on day 21 by decapitation.
The ventral midbrain containing the SNpc was dissected
and stored at −80 °C for further experiments.
Quantitative reverse transcription (qRT‑PCR) analysis
Total RNA from SNpc tissues or BV-2 cells were extracted
using RNAiso Plus Reagent (Takara, Dalian, China) and
reverse transcription was performed with the
SuperScriptIII First-Strand Synthesis system. Quantitative assay of
genes expressions was performed using a SYBR QPCR
Kit (Toyobo, Osaka, Japan) and ABI 7500 real-time PCR
system (Applied Biosystems, CA, USA). The gene
expression was normalized to the GAPDH and calculated using
the ΔCT method. The specific primer sequences used were
listed in Table S1.
The mice were evaluated for motor balance and
coordination using a rotary rod apparatus (Harvard Apparatus, MA,
USA) at different times as indicated. All animals were
pretrained before staring the experiment. Each mouse was
placed in the apparatus (diameter: 7 cm, length: 30 cm)
and operates at a constant speed of 30 rpm. The three
latencies to fall recorded by magnetic trip plates were
averaged to yield a final value, and the maximum cutoff time
was set as 180 s.
A wooden pole of ~ 50 cm in length and ~ 1 cm in diameter
was wrapped in gauze and a cork ball of 2.5 cm was glued
on top of the pole. Each mouse was placed on top of the ball
and the time required for the mouse to climb down the pole
was recorded. The test was repeated three times to evaluate
the average. The cutoff time was 250 s.
The mice were suspended by their forepaws to a horizontal
wire. The mouse was scored as 3 if grasped the wire with
two hind paws, 2 if grasped the wire with one hind paw,
and 1 if grasped the wire with any of the hind paws.
Each mouse was placed at one end of a 100 cm long and
2 cm wide beam, which was elevated 1 cm above the
ground. The time required for the mouse to cross the beam
was measured. The cutoff time was set as 120 s.
The midbrain tissues were fixed in 4% paraformaldehyde,
embedded in paraffin, and cut into 4 μm thick sections.
For Nissl staining, the sections were incubated with nissl
staining solution at 50 °C for 20 min. After rinsing with
distilled water, sections were dehydrated with 95% ethyl
alcohol, 70% ethyl alcohol in secession. The number of
staining cells in SNpc was counted using a BX51 light
microscope (Olympus, Tokyo, Japan) at higher
magnification (× 400).
Sections of brain tissues were permeabilized with Triton
X-100 and blocking with 1% goat serum in saline at room
temperature, and incubated with a primary antibody to TH
at 1:200 dilution at 4 °C overnight. After washing with
saline, sections were incubated with secondary
goat–rabbit IgG antibody for 1 h at room temperature and washed
three times. DAB solution was added to incubate for 3 min.
Images were captured with a BX51 light microscope.
Total protein was extracted from selected mouse midbrain
or BV-2 cells using RIPA lysis buffer, and quantified using
a bicinchoninic acid protein assay kit (Thermo, MA, USA).
Western blotting was performed as previously described
]. Different primary antibodies used were as following:
TH, α-syn, β-actin, ASC (diluted 1:1000), Nlrp3 and
Caspase-1 (diluted 1:500). After incubation with
corresponding secondary antibody (HRP-conjugated goat anti-rabbit
or donkey anti-goat IgG antibody, diluted 1:1000), bands
were visualized with the Enhanced Chemiluminescence Kit
and determined with a densitometry software (Image J, NIH,
Enzyme‑linked immunosorbent assay (ELISA)
The level of TNF-α, COX-2, iNOS, BDNF, IL-18 and IL-1β
in SNpc was determined using immunoassay kits with the
instructions provided by manufacturer (R&D System, MN,
USA). All samples were assayed and absorbance was read
using a microplate reader (Multiskan Spectrum, Thermo,
Murine BV-2 microglial cells were obtained from the Cell
Bank of Chinese Academy of Medical Science (Shanghai,
China) and were maintained in Dulbecco’s modified Eagle’s
medium with 10% heat-inactivated FBS, 100 U/mL
penicillin and 100 mg/mL streptomycin at 37 °C in a humidified
incubator under 5% CO2 condition.
In vitro miR‑30e mimics transfection
For overexpression of miR-30e in BV-2 cells, the cells were
transfected with miR-30 mimics or negative control miRNA
using Lipofectamine 2000 according to the manufacturer’s
protocol. After 48-h transfection, cells lysis was used for
luciferase assay or western blotting analysis.
Luciferase reporter assay
The binding of miR-30e to the target gene Nlrp3 was assayed
by luciferase experiment. A wild-type murine Nlrp3 mRNA
3′UTR luciferase reporter construct was amplified by PCR
from the Nlrp3 mRNA (NM_145827) 3′-UTR sequence and
then cloned into the psiCHECK2-3′UTR vector (Ambio Inc.,
TX, USA). For mutant construct of Nlrp3 3′UTR, deletion
mutagenesis and fusion-PCR were performed. BV-2 cells
were co-transfected with either wild-type or mutant Nlrp3
3′UTR, plus miR-30e mimics or negative control for 48 h.
Luciferase activity was assessed using Dual-Luciferase
Reporter Assay System (Promega, WI, USA) according to
the manufacturer’s instructions.
Data were presented as mean ± SEM. The statistical
significance of differences between two groups was analyzed
by one-way analysis of variance (ANOVA) or the unpaired
two-tailed Student’s t test using SPSS 10.0 statistical
software (SPSS Inc., IL, USA). P < 0.05 was considered to be
First, we examined the expression of miR-30e in SNpc
of MPTP-treated mice by qRT-PCR. The results showed
that the expression of miR-30e was significantly decreased
after intraperitoneal injection of MPTP. At 3, 7, 10 and
14 days after the first MPTP injection, miR-30e
expression was reduced to 0.91 ± 0.08-fold, 0.84 ± 0.07-fold,
0.61 ± 0.07, and 0.53 ± 0.06-fold of saline-treated mice,
respectively (Fig. 1).
Effect of miR‑30e agomir on body weight in MPTP‑administrated mice
To investigate the role of miR-30e in MPTP-PD mice,
miR30e agomir or negative control was injected into the right
lateral ventricle of MPTP-PD mice to restore the expression
of miR-30e. Expectedly, the expression of miR-30e in SNpc
was markedly higher in miR-30e agomir-treated mice than
in negative control-treated mice at 21 days after the first
MPTP injection (Fig. 2a). Intraperitoneal injection of MPTP
dramatically decreased body weight of mice compared
to saline group. However, miR-30e agomir significantly
improved body weight on day 21 in MPTP-administrated
mice (Fig. 2b).
MiR‑30e upregulation improved the dyskinesia induced by MPTP
To investigate the effect of miR-30e restoration on motor
function, several kinds of behavior tests, including rota-rod
test, pole test, traction test and beam-crossing task were
conducted in the present study. The results of rota-rod test
showed that MPTP injection significantly decreased rota-rod
activity as compared to saline group. However, treatment
with miR-30e agomir for 3 and 7 days showed significant
improvement in rota-rod activity (Fig. 3a). Pole test showed
that total locomotor activity was markedly increased at 1st,
3rd and 7th days after the last MPTP injection, which was
significantly inhibited at 3rd and 7th days after the first
miR30e agomir treatment (Fig. 3b). Furthermore, traction test
showed that MPTP caused a significant decrease in limb
movements scored compared with saline group. However,
miR-30e agomir delivery time-dependently increased the
limb movements scored (Fig. 3c). Finally, MPTP
significantly increased the time required for the mouse to cross the
group. b MiR-30e upregulation attenuated the decrease of body
weight in MPTP-PD mice. **P < 0.01 vs. saline; ##P < 0.01 vs.
MPTP, n = 18 mice in each group
Fig. 3 MiR-30e upregulation
improved the dyskinesia in
MPTP-PD mice. a–d Effect of
miR-30e restoration on rota-rod
test (a), pole test (b), traction
test (c), and beam-crossing task
(d) at 1, 3 and 7 days after the
first miR-30e agomir treatment,
respectively. **P < 0.01 vs.
saline; ##P < 0.01 vs. MPTP,
n = 12–16 mice in each group
beam, whereas miR-30e upregulation decreased the latency
time on the beam at 3rd and 7th days after the first miR-30e
agomir treatment (Fig. 3d). Collectively, these data suggest
that miR-30e overexpression can effectively improve the
dyskinesia in PD mice model.
These results suggest that miR-30e protects against
MPTPinduced neuronal damage and dopaminergic neuronal loss.
Effect of MiR‑30e on inflammatory markers and BDNF levels in MPTP‑PD mice
MiR‑30e attenuated dopaminergic neuronal loss and α‑syn expression in SNpc of MPTP‑PD mice
To confirm the effect of miR-30e on neuronal activity, nissl
staining was used to detect the level of nissl substance in
SNpc. The results showed that the level of nissl substance
was gradually decreased at 1st, 3rd and 7th days after the
first MPTP injection (Figure S2). However, treatment with
miR-30e agomir significantly restored the loss of nissl
substance (Fig. 4a). We also determined the effect of miR-30e
upregulation on dopaminergic neuronal loss in SNpc of
MPTP-PD mice. MPTP resulted in a significant decrease in
the number of TH-positive cells, and treatment with
miR30e markedly attenuated this TH loss in SNpc (Fig. 4b).
Similarly, western blotting showed that upregulation of
miR-30e could inhibit MPTP-induced decrease of TH
protein expression. Moreover, we found that MPTP increased
α-syn expression, whereas miR-30e agomir treatment was
associated with decreased α-syn expression (Fig. 4c, d).
Since that α-syn-induced neuroinflammaiton has an
important role in the pathogenesis of PD [
], we next detected the
effect of miR-30e on inflammation in SNpc tissues. ELISA
results showed that MPTP injection significantly increased
the secretion of inflammatory mediators, TNF-α, COX-2 and
iNOS. However, miR-30e treatment markedly suppressed the
secretion of these inflammatory mediators induced by MPTP
(Fig. 5a–c). In addition, the level of BDNF was significantly
lower in the MPTP group than in saline group, and miR-30e
agomir treatment could restore the decrease of BDNF level
Nlrp3 is a target gene of miR‑30e
To explore the mechanisms underlying the
neuroprotective effect of miR-30e, we analyzed the potential targets
predicted for miR-30e. By using miRNA target gene
prediction website (http://www.microrna.org/), we found
that Nlrp3 was predicated as a putative target with a
conserved miR-30e binding sites in its 3′UTR (Fig. 6a).
Fig. 4 Exogenous delivery of miR-30e agomir protected against
neuronal damage and dopaminergic neuronal loss in MPTP-induced
PD mice model. a The nissl staining in SNpc. b Immunostaining of
TH-positive neurons in the SNpc. c The protein expressions of TH
and α-syn were determined by western blotting. d Densitometric
analysis of TH and α-syn protein expression. **P < 0.01 vs. saline;
##P < 0.01 vs. MPTP, n = 6–8 mice in each group
Fig. 5 Effect MiR-30e agomir
on inflammatory markers and
BDNF levels in MPTP-PD
mice. a–d The level of TNF-α
(a), COX-2 (b), iNOS (c)
and BDNF (d) in SNpc were
immunoassay kits. **P < 0.01 vs. saline;
##P < 0.01 vs. MPTP, n = 6
mice in each group
Fig. 6 MiR-30e negatively
regulated Nlrp3 expression. a
Alignment of miR-30e binding site
to Nlrp3 3′UTR was shown. b
Luciferase activity in BV-2 cells
transfected with wild-type or
mutant Nlrp3 3′UTR reporter.
c BV-2 cells were transfected
with different concentrations
of miR-30e mimics (5, 10, 20
or 40 nmol/L) for 48 h. Nlrp3
mRNA expression was
determined by qRT-PCR. d Western
blotting analysis of Nlrp3 in
BV-2 cells transfected with
miR-30e mimics or negative
control. *P < 0.05, **P < 0.01
vs. control, n = 6
When we co-transfected BV-2 cells with miR-30e mimics
and wild-type or mutant Nlrp3 3′UTR reporter, luciferase
assay showed that miR-30e overexpression significantly
decreased the luciferase activity of wild-type Nlrp3 3′UTR
reporter but not in the mutant one (Fig. 6b), suggesting
that miR-30e directly binds the mRNA encoding Nlrp3.
In consistence, transfection with miR-30e mimics
dosedependently decreased Nlrp3 mRNA expression (Fig. 6c).
We also detected the effect of miR-30e mimics on
endogenous Nlrp3 protein expression. Western blotting showed
that miR-30e overexpression effectively decreased the
protein expression of Nlrp3 (Fig. 6d).
MiR‑30e suppressed Nlrp3 inflammasome activation in SNpc of MPTP‑PD mice
Because of the crucial role of miR-30e in regulating Nlrp3
expression, we determined whether miR-30e controls the
activity of Nlrp3 inflammasome in SNpc of MPTP-PD
mice. Western blotting showed that the protein
expressions of Nlrp3, ASC and Caspase-1 were significantly
increased in MPTP-PD mice whereas the protein
expression of Procaspase-1 was not altered. However, miR-30e
upregulation abolished MPTP-induced increase of Nlrp3,
ASC and Caspase-1 expressions (Fig. 7a, b). Moreover,
the elevation of IL-18 and IL-1β secretions was markedly
Fig. 7 MiR-30e upregulation
attenuated Nlrp3 inflammasome
activation in SNpc of MPTP-PD
mice. a Western blotting
analysis of Nlrp3, ASC, Procaspase-1
and Caspase-1 protein
expressions. b Densitometric analysis
of the above genes protein
expressions. c, d The level of
IL-18 (c) and IL-1β (d) in SNpc
were determined using
immunoassay kits. **P < 0.01 vs.
saline; ##P < 0.01 vs. MPTP,
n = 5 mice in each group
inhibited in MPTP-induced PD mice treated with miR-30e
agomir (Fig. 7c, d). We also detected the mRNA levels of
the Nlrp3 inflammasome. The results showed that MPTP
injection significantly increased the mRNA expressions of
Nlrp3, Caspase-1, ASC, IL-18 and IL-1β as compared with
saline group. MiR-30e agomir treatment was associated with
decreased expression of the above genes (Figure S3 A–E).
This study uncovers a link between miR-30e and Nlrp3
inflammasome-mediated neuroinflammation in the
pathogenesis of PD. We provide convinced evidence that miR-30e
improves neuronal damage, neuroinflammaiton and
dyskinesia via negatively regulating Nlrp3 expression and
inhibiting NLRP3 inflammasome activation in MPTP-induced
PD mice model. MPTP is the most valuable neurotoxin for
inducing animal PD model that producing many features of
the biological and pathological changes similar to human
]. After rapidly crossing the blood–brain barrier by
systemic injection, MPTP is taken up by the astrocytes and
catalyzed into the toxic moiety that can be transported into
dopaminergic neurons, leading to neuronal damage and
]. Thus, here, we used MPTP to stimulate
dopaminergic neuron loss in vivo to induce PD.
MiRs have been shown to act at the post-transcriptional
level by binding the 3′UTR of their target mRNA, leading
to degradation of the target gene expression [
]. To date,
there are a few studies revealing the critical role of miRs in
the pathogenesis of PD. For example, miR-133b expression
was found to be decreased in the midbrain of PD patients as
well as in mouse models [
]. Moreover, miR-124 targeted
to bim and in turn inhibited dopaminergic neurons loss, a
key event during the development of PD [
]. In addition,
miR-7, miR-153 and miR-155 negatively regulated α-syn
expression, which is a crucial regulator for
neuroinflammation in PD [
]. In the present study, we investigated the
alteration of miR-30e in SNpc by qRT-PCR and the results
showed that the expression of miR-30e was downregulated
gradually after MPTP injection, suggesting miR-30 might
also have a role in the pathogenesis of PD.
Although miR-30e has been shown to be involved in the
regulation of glioma cells differentiation and invasion [
], the exact role of miR-30e in PD has not been shown
previously. As mentioned in the evidence cited above, MPTP
administration is known to decrease neuronal activity and
the density of TH-positive neurons, indicating degeneration
of the dopaminergic neurons in SNpc [
4, 8, 22
deficiency of dopamine level makes patients suffer from different
degree of behavioral motor deficit . In the current study,
our results showed that MPTP injection produced behavior
disorder, as evidenced by rota-rod test, pole test, traction
test and beam-crossing task. However, delivery of miR-30e
agomir in midbrain effectively prolonged the duration time
of mice on rotating-stick, decreased the latency to cross
straight run way on narrow beam, and increased the grasping
force as well as the rate of climbing pole. Furthermore, we
investigated whether miR-30e upregulation improves motor
function through protecting against MPTP-induced neuronal
damage. Nissl staining showed that restoration of miR-30e
in PD mice could increase the neuronal activity. In addition,
the loss of TH activity as well as a decrease in TH protein
expression is thought to contribute to dopamine deficiency,
which is the most prominent at media levels of SNpc [
Immunohistochemistry and western blotting analysis for TH
expression revealed that the loss of dopamine neuron in PD
mice was dramatically less pronounced after miR-30e
agomir delivery. These results indicate that miR-30e can protect
against neuronal injury in MPTP-induced PD mice model.
It has been reported that excessive accumulation of α-syn
is a pathological hallmark of PD patients, especially in SNpc
]. Here, we demonstrated that miR-30e
overexpression could effectively attenuate MPTP-induced the increase
of α-syn expression in SNpc. Considering that
α-syntriggered neuroinflammation has an important in the
pathogenesis of PD , we also examined the effect of miR-30e
on inflammatory cytokines secretion in SNpc. The results
showed that miR-30e upregulation almost abolished the
increase of TNF-α, COX-2 and iNOS secretion. Moreover,
aberrant alterations in BDNF expression or signaling may
contribute to neurodegeneration and sustained decreased
BDNF mRNA expression can be observed in SNpc of PD
]. In this study, we found that the reduction of
BNDF secretion in SNpc was markedly reversed by miR-30e
Finally, we explored the mechanisms by which miR-30e
inhibited neuroinflammation in SNpc of PD mice.
Intriguing, although MPTP-induced α-syn expression was inhibited
by miR-30e agomir, we found that the luciferase activity of
α-syn was not affected by miR-30e (data not shown),
suggesting α-syn is not the direct target of miR-30e. Notably,
α-syn has been recognized to induce the IL-1β production in
a process that depends, at least partially, on Nlrp3
]. In the current study, we demonstrated for the
first time that Nlrp3 was a potential target of miR-30e. The
luciferase assay indicated that miR-30e targeted the 3′UTR
region of Nlrp3 to negatively regulate Nlrp3 mRNA and
protein expression. In response to a variety of inflammatory
stimuli, the Nlrp3 inflammasome, along with the adaptor
protein ASC, induces the activation of Caspase-1 and the
maturation of proinflammatory cytokines IL-18 and IL-1β,
leading to trigger inflammation [
]. Accordingly, our
results showed that Nlrp3, ASC and Caspase-1 expressions,
and IL-18 and IL-1β secretions were all increased in SNpc
of PD mice. However, miR-30e restoration abolished the
above elevations. Consistent with the protein expressions in
SNpc, the mRNA levels of the Nlrp3 inflammasome were
also decreased after miR-30e agomir treatment. These data
suggest that the activation of Nlrp3 inflammasome may
contribute to MPTP-induced neuroinflammation in SNpc,
whereas miR-30e inhibits this process by targeting Nlrp3.
Furthermore, considering the critical role of Nlrp3
inflammasome in the development of neurodegenerative diseases
6, 12, 13
], our study also indicate that miR-30e induces
neuron regeneration at least partially via inhibition Nlrp3
In conclusion, our study demonstrates that miR-30e
negatively regulates Nlrp3 expression, which in turn attenuates
neuroinflammation in SNpc of PD mice through inhibiting
Nlrp3 inflammasome activity. These findings indicate that
targeting miR-30e by a genetic approach may provide a
novel strategy for the treatment of PD.
Compliance with ethical standards
Conflict of interest The authors declare that they have no potential
conflicts of interest.
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