Download Mitochondrial diseases affecting nervous system and muscle

Mitochondrial diseases affecting nervous system and muscle
Prof. Isidro Ferrer, Institut Neuropatologia, Servei Anatomia Patològica, IDIBELL-Hospital Universitari
de Bellvitge, Universitat de Barcelona, CIBERNED, Hospitalet de LLobregat; Spain
Respiratory chain is composed of complexes located at the inner mitochondrial membrane:
Complex I: NADH ubiquinone reductase
Complex II: succinate: ubiquinone oxidoreductase
Complex III: ubiquinol cytochrome c reductase
Complex IV: cytochrome C oxidase
Complex V: ATP synthase
Final goal: production of ATP
Respiratory chain proteins are synthesized from two different genomes: mtDNA and nDNA
•mtDNA encodes 13 respiratory chain polypeptides, 2 rRNAs and 22 tRNAs
•nDNA encodes the majority of respiratory chain polipeptides
Transport of cytosolic proteins and their assembly with mitochondrial-encoded proteins, and proteins
needed for mitochondrial transcription and translation, and mitochondrial RNA metabolism are also
encoded by nDNA.
Primary mitochondrial diseases (mitochondrial cytopathies, systemic, cerebral, endocrine and muscular,
and combinations of all of the them) are the consequence of dysfunctions of both mitochondrial and
nuclear genes either separately or in combination. As a result, oxidative phosphorylation (OXPHOS) is
defective. Several complexes can be damaged, although the most common deficiencies affect
complexes I and IV.
Mitochondrial diseases affecting nervous system and muscle
Chronic progressive external
opthalmoplegia (CPEO)
External optahlmoplegia, bilateral ptosis, mild proximal myopathy
Progressive myopathy
Progressive myopathy influenced by physical efforts, ragged-red fibers
Infantile myopathy and lactic
acidosis
Hypotonia, feeding and respiratory difficulties. Fatal and non-fatal forms
Kearns-Sayre syndrome (KSS)
PEO, pigmentary retinopathy, cerebellar ataxia, heart block, ↑ proteins in CSF,
myopathy. Bilateral deafness, dysphagia, diabetes mellitus, hypoparathyroidism,
Mitochondrial encephalomyopathy
with lactic acidosis and stroke-like
episodes (MELAS)
Stroke-like episodes before the age of 40, dementia, seizures, ragged-red fibers,
lactic acidosis. Cardiomyopathy, diabetes mellitus, bilateral deafness, cerebellar
ataxia, pigmentary retinopathy, dementia, peripheral neuropathy
Myoclonic epilepsy with ragged
red fibers (MERFF)
Myoclonus, epilepsy, cerebellar ataxia, myopathy with ragged-red fibers. Dementia,
optic atrophy, deafness, peripheral neuropathy, optic atrophy, multiple lipomas
Leigh syndrome
Relapsing encephalopathy, presenting mainly in infancy, cerebellar ataxia, brain
stem and basal ganglia involvement. Basal ganglia lucencies. Optic atrophy,
peripheral neuropathy
Neurogenic weakness with ataxia
and retinitis pigmentosa (NARP)
Ataxia, peripheral neuropathy, pigmentary retinopathy. Basal ganglia lucencies,
abnormal electroretinogram
Mitochondrial neurogastrointestinal
encephalomyopathy (MNGIE)
CPEO, gastrointestinal pseudo-obstruction, peripheral neuropathy, miopathy. Diffuse
leucoencephalopathy
Leber hereditary optic neuropathy
(LHON)
Visual failure at about 25 years, males/females: 4/1, dystonia, cardiac pre-excitation
syndromes
Alpers syndrome
Refractory seizures in childhood, microcephaly, cognitive impairment, hypotonia,
ataxia, sensitivity to valproate. Liver damage from fat liver to cirrhosis
MNGIE myo- and neurogastrointestinal encephalopathy
Gastrointestinal dysmotility, mild leucoencephalopathy with T2 hyperintensities on
MR imaging
Molecular genetics of main mitochondrial disorders
mtDNA mutations
large-scale rearrengements
deletions Chronic progressive external ophtalmoplegia (CPEO), Kearns-Sayre syndrome (KSS), Pearson
syndrome (marrow-pancreas síndrome)
duplications
point mutations in tRNAs or rRNAs
•MELAS
•MERRF
•Mitochondrial cardiomyopathy and myopathy
point mutations in protein coding genes
•ATP6 mutations: NARP, Leigh syndrome
•Complex I mutations: Leber hereditary optic atrophy (LHON)
•Complex IV (COX) subunit mutations
Nuclear gene mutations
•Autosomal dominant and autosomal recessive progressive external ophtalmoplegia (AdPEO, ArPEO)
•MNGIE: myogastrointestinal encephalopathy: mutations in thymidine phosphorylase gene (22q13)
•Wolfram syndrome (DID-MOAD): mutations in wolframin gene (4p16) associated with large scale mtDNA
deletions
•Leigh syndrome caused by nuclear gene mutations affecting complexes I, II or IV
•Infantile hypertrophic cardiomyopathy and encephalomyopathy: mutations in SCO2 gene
Mutations in other mitochondrial protein genes
•Hereditary spastic paraplegia linked to 16q24
•Friedreich ataxia, mutations in the frataxin gene in 9q13
Mitochondrial myopathy
A
B
C
D
Peripheral aggregates (A) are usually strongly stained with trichrome (B) and show increased SDH
immunoreactivity (C) (arrows). This is often acconmpanied by COX negative, SDH positive fibers (D,
short arrow)
Mitochondrial myopathy
Red aggregates (arrows) as seen in mitochondrial myopathie stained with trichrome
Mitochondrial myopathy
Abnormal mitochondria in muscle fibers with altered morphology and crystalline inclusions
Chronic progressive external ophtalmoplegia (CPEO)
A
B
C
D
Ragged-red fibers as seen following H-E staining (A); mild accumulation of punctate red deposits with .modified
trichrome (B); SDH enhancement in the periphery of the fibers; and increased COX staining of scattered fibers
Abnormal mitochondria in muscle fibers with aberrant morphology and crystalline inclusions accompanied by lipofuscin
deposits
Mitochondrial myopathy
A
B
C
D
E
F
Mild variation in fiber size (A) accompanied by increased NADH (B) and SDH staining in the periphery of certain fibers (C)
and within small fibers (D, E, respectively), and COX negative SDH positive fibers (F)
Abnormal mitochondria in muscle fibers with giant size and altered morphology of the cristae
Mitochondrial myopathy and complex I deficiency
*
*
A: Several muscle fibers show sub-sarcolemmal deposits (arrows);
B: two ragged red fibers (asterisks)
Mitochondrial myopathy and complex I deficiency
Large numbers of abnormal mitochondria in muscle fibers. Elongated mitochondria show abnormal cristae and
crystalline inclusions
Kearns-Sayre
*
A
B
C
*
D
E
F
G
H
I
A, E: H-E, variation in fiber size, sub-sarcolemmal deposits (arrows); B NADH, increased signal in
individual fibers (asterisk); C: ATPase pH 4.3, variation in fiber size and one ragged red fiber (short arrow);
D: Oil red O showing increased lipid droplets in two fibers; F, SDH, blue-ragged fiber (asterisk); G-I: semithin sections stained with toluidine blue, sub-sarcolmmal deposits (arrows): ragged-red fibers.
Kearns-Sayre
Increased numbers of mitochondria with
abnormal cristae and dense intramitochondrial
inclusions
Kearns-Sayre
50 kDa
45 kDa
30 kDa
22 kDa
20 kDa
Ponceau
50 kDa
P
PC
Co
CcC
C
CC
Med edC
P: pons proband; PC: pons control; Co: cerebral cortex proband; CoC: cerebral cortex control; C: cerebellum
proband; CC: cerebellum control; Medc: medulla oblongata control; Med: medulla oblongata proband
Gel electrophioresis and western blotting to different sub-units of respiratory chain components in control and
Kearns-Sayre case processed in parallel.
Kearns-Sayre
Cco
CP
1,6
I07-109
pr otuber anci a
pons
2%
1,4
Cerebral
cortex
I07-109 cor teza
1,2
19%
1
1,2
1
0,8
0,8
0,6
28%
23%
21%
-20%
0,6
-48%
0,4
-59%
0,4
-37%
-87%
0,2
0,2
0
0
ATPsisynth
c reduc
ATP
ntasa ciCyt
t-r eductasa
SDH
SDH
COX
COX
NADH
NADH
ATPsynth
si ntasa ci
t-r eductasa
ATP
Cyt
c reduc
cerebellum
I07-109 cer ebel o
1,6
1,6
1,4
COX
COX
NADH
NADH
CB
CC
1,8
SDH
SDH
1%
medulla
oblongata
I07-109 bulbo
1,4
-10%
1,2
1,2
-1%
1
1
-28%
-37%
0,6
-10%
0,8
0,8
-50%
-59%
0,4
-20%
0,6
-48%
0,4
0,2
0,2
0
ATP si ntasa
ci t-
ATP synth rCyt
c reduc
eductasa
SDH
SDH
COX
COX
NADH
NADH
0
ATP
synth
ATP sintasa
Cyt c reduc
cit-reductasa
SDH
SDH
COX
COX
NADH
NADH
Expression levels of ATP synthase; cytochrome c reductase; succino dehydrogenase (SDH); cytochrome c oxidase
(COX); reduced nicotinamide adenine dinucleotide (NADH) in the pons, cerebral cortex, cerebellum and medulla
oblongata of one control and one case of Kearns-Sayre. Reduced expression levels of several subunits are observed in
the majority of brain regions in Kearns-Sayre case.
Mitochondrial leucoencephalopathy in infancy with lactic acidosis
Atrophy of the cerebral cortex, caudate and putamen, and thalamus, together with reduced cerebral white
matter, periventricular demyelination, and enlargement of the lateral ventricles. Demeylination of the
cerebellar white matter. Klüver-Barrera staining.
Mitochondrial leucoencephalopathy with lactic acidosis in infancy
A
B
C
D
G
H
A
E
F
A, B and C: variable neuron loss, spongiosis and focal necrosis in the cerebral cortex; D: cystic necrosis in the white
matter; E: mineralisation of thalamic neurons; F: neuron loss and marked astrocytic gliosis in the cerebellar cortex; G,
H: myelin loss, spongiosis and vascular proliferation in the white matter. H-E staining
Mitochondrial leucoencephalopathy with lactic acidosis in infancy
Myopathy with abnormal mitochondria. Increased numbers of large mitochondria with abnormal cristae in
muscle fibers.
Leigh syndrome
A
D
C
B
E
F
A: bilateral necrosis of the putamen; B: cystic necrosis of the basal ganglia; C: demyelination of the cerebellar white
matter and pyramidal tracts; D: multiple foci of infarct-like lesions in the pons; E: cystic necrosis of the optic nerves; F:
vacuolization of the white matter of the centrum semi-ovale.
Leigh syndrome
A
B
C
D
E
F
A: subthalamus; B: white matter; C: putamenr (PAS stain); D: substantia nigra; E: cerebral white matter; and F:
cerebellar white matter (CD68, microglia). Neuron loss, severe white matter involvement, edema, endothelial
hyperplasia and microglial activation.
Alpers syndrome
A
C
B
D
E
A: marked atrophy of the cerebral
cortex, basal ganglia and cerebellum;
B: atrophy of the cerebral cortex and
caudate; reduced white matter; C:
neuronal loss and gliosis of the
cerebral cortex; D: neuronal loss and
spongiosis in the upper cortical layers;
E: marked loss of granule cells and
Purkinje cells in the cerebellar cortex.
MELAS
*
A
D
B
*
C
E
A-C: infarct-like lesions in the cerebral cortex (arrows) and bilateral lucencies in the basal ganglia (asterisks); D:
subsarcolemmal slight increase of SDH activity; E: abnormal mitochondria with crystalline inclusions in muscle
fibers.
Neuropathy, ataxia, retinitis pigmentaria: NARP
8993 T > G mutation of the mtDNA
I
II
1
A
2
3
4
5
6
7
B
A: Atrophy of the cerebral cortex and enlargement of the ventricles, bilateral putaminal hypodensities (arrows). B: Moderate
atrophy of the insular region, enlargement of the lateral ventricles, cystic necrosis in the putamen and marked atrophy of the
optic pathways
Neuropathy, ataxia, retinitis pigmentaria (NARP)
A: Cerebellar atrophy. B, C: Marked neuronal loss and gliosis in the Purkinje and granular cell
layers of the cerebellum, together with focal necrosis in the molecular layer. D: Axonal torpedo in
the cerebellum. A-C haematoxylin and eosin; D immunohistochemistry to phosphorylated
neurofilaments.
Neuropathy, ataxia, retinitis pigmentaria (NARP)
A: Neuron loss, mainly in the upper layers of the lateral geniculate nucleus. b Loss of neurons and gliosis in the dorsal
cochlear nucleus. C: Neuron loss in the olfactory bulb. A: Kluver-Barrera; B and C: haematoxylin and eosin.
A: Cystic and submassive necrosis in the putamen.
B: Neuron loss and cysts in the caudate. H-E.
Neuropathy, ataxia, retinitis pigmentaria (NARP)
Temporal muscle. A: Variation in fibre size as seen in modified Gomori’s trichrome stained
sections. B, C: Increased subsarcolemmal oxidative staining in scattered muscle fibers as
seen with SDH (B) and cytochrome c oxidase (C) histochemistry. Cryostat sections.
MNGIE: myo- and neuro-gastrointestinal leucoencephalopathy
POLIP: polyneuropathy, ophtalmoplegia, leucoencephalopathy and intestinal pseudo-obstruction;
OGIMD: oculo-gastro-intestinal muscular dystrophy; MEPOP: mitochondrial encephalomyopathy,
sensorimotor polyneuropathy, ophtalmoplegia and pseudo-obstruction
White matter hyperlucencies (often asymptomatic)
Atrophy of the muscular layers of the colon
MNGIE: myo- and neuro-gastrointestinal leucoencephalopathy: POLIP
A
B
C
D
Combination of denervation atrophy and mitochondriopathy. A. A large group of atrophic fibers; and B. Target fibers
consistent with denervation; C and D: Increased SDH reaction in COX negative fibers
Wolfram syndrome: diabetes insipidus, insulin-dependent diabetes mellitus, optic neuropathy and
deafness
*
Atrophy of the olfactory bulbs and tracts (white arrows), atrophy
of the optic nerves and chiasm (asterisk), atrophy of the
cochlear nerve, mild olivopontocerebellar atrophy.
Mutations in wolframin gene (endoplasmic reticulum-related protein) and large-scale mtDNA deletions in some patients
Wolfram syndrome
A
B
C
D
E
F
A: loss of Purkinje cells, and axonal torpedoe; B: atrophy of the optic nerve; myelin basic protein immunostaining; C:
atrophy of the superior colliculus; D: loss of fibers in the cochlear nerve; E: cochlear nucleus; F: moderate neuron loss
in the inferior olive