Welcome to the Clinical Center Grand Rounds,
a weekly series of educational lectures for physicians and
health care professionals broadcast from the Clinical
Center at the National Institutes of Health in
Bethesda, MD.
The NIH Clinical Center is the world's largest hospital totally
dedicated to investigational research and leads the global
effort in training today's investigators and discovering
tomorrow's cures.
Learn more by visiting us online at http://clinicalcenter.nih.gov
TODAY WE WELCOME OUR SPEAKERS,
DR. DEREK NARENDRA AND CHIEF OF
THE INHERITED MOVEMENT DISORDERS
UNIT, AND DR. CLAIRE LE PICHON,
DIVISION OF INTRAMURAL RESEARCH
IN THE EUNICE KENNEDY SHRIVER
NATIONAL INSTITUTE OF CHILD
HEALTH AND HUMAN DEVELOPMENT.
DR. NARENDRA EARNED HIS BACHELOR
FROM COLUMBIA UNIVERSITY, AND
MEDICAL DEGREE FROM THE
UNIVERSITY OF MICHIGAN.
THROUGH HIS GRADUATE RESEARCH,
HE IDENTIFIED A NOVEL MITOPHAGY
PATHWAY THROUGH THE COORDINATED
ACTIVITIES OF PARKIN AND PINK1,
MUTATIONS WHICH ARE THE LEADING
CAUSE OF EARLY ONSET PARKINSON'S
DEED.
DISEASE.
COMPLETED NEUROLOGY RESIDENCY
TRAINING AT THE BRIGHAM AND
WOMEN'S HOSPITAL AND
MASSACHUSETTS GENERAL HOSPITAL
HARVARD PROGRAM IN 2016, WITH
ADDITIONAL FELLOWSHIP TRAINING
OF MOVEMENT DISORDERS AT
UNIVERSITY OF PENNSYLVANIA.
IN 2017, DR. NARENDRA RECEIVED
THE TRANSITION TO INDEPENDENCE
AWARD AND JOINED NINDS AS A
CLINICAL -- ASSISTANT CLINICAL
INVESTIGATOR WITHIN THE
NEUROGENETICS BRANCH.
HIS LABORATORY FOCUSES ON
MITOCHONDRIAL DYSFUNCTION AND
STRESS RESPONSES IN DISORDERS
SUCH AT PARKINSON'S DISEASE,
ALS.
IN 2020 HE RECEIVED A LASKER
CLINICAL RESEARCH SCHOLARSHIP
AND BECAME A TENURE TRACK
INVESTIGATOR.
DRTHE MOVEMENT DISORDER SOCIETY
AND AMERICAN NEUROLOGICAL
ASSOCIATION AND IN 2022, HE
RECEIVED AN AWARD IN
NEUROSCIENCE.
OUR SECOND SPEAKER IS DR. CLAIRE
LE PICHON.
DR. LE PICHON EARNED HER
BACCALAUREATE FROM UNIVERSITY OF
CAMBRIDGE IN THE UNITED KINGDOM
AND HER PH.D. IN BIOLOGICAL
SCIENCES FROM COLUMBIA
UNIVERSITY IN 2007.
AT COLUMBIA, IN A LABORATORY OF
DR. STUART FIRESTEIN, SHE
DEVELOPED HER INTEREST IN
NEURODEGENERATIVE DISEASE WHILE
STUDYING THE FUNCTION OF THE
CELLULAR PRION PROTEIN, PRPC.
AFTER HER GRADUATE STUDIES,
DR. LE PICHON JOINED GENERAL
TECHGENENTECH,PRE-CLINICAL DRUGT
FOR NEURODEGENERATIVE DISEASES.
IN 2013, SHE JOINED THE NATIONAL
INSTITUTE OF NEUROLOGICAL
DISORDERS AND STROKE AS A SENIOR
RESEARCH FELLOW AND IN 2016, SHE
WAS INVITED TO BECOME A TENURE
TRACK INVESTIGATOR IN NICHD.
DR. LE PICHON'S LABORATORY
EMPLOYS A MULTIDISCIPLINARY
APPROACH USING MOUSE MODELS AND
HUMAN IPSC-DERIVED NEURONS TO
INVESTIGATE THE EARLY EVENTS
UNDERLYING THE ONSET AND
PROGRESSION OF NEURODEGENERATIVE
DISEASE.
DR. LE PICHON EARNED THE NIH'S
DIRECTOR'S AWARD, THE
KIRSCHSTEIN AWARD FOR MENTORING
IN 2021, AND RECEIVED NUMEROUS
NICHD SCIENTIFIC DIRECTORS
AWARDS AND MERIT AWARDS.
SHE IS A MEMBER OF THE AMERICAN
SOCIETY FOR CELL BIOLOGY AND
SOCIETY FOR NEURAL SCIENCE AND
IS A NATIONALLY AND
INTERNATIONALLY RECOGNIZED
SPEAKER IN THE FIELD OF
NEURODEGENERATIVE DISEASES.
PLEASE WELCOME OUR FIRST
SPEAKER, DR. NARENDRA, LESSONS
FROM GENETICS.
WELL, THANK YOU FOR THAT
INTRODUCTION AND FOR THE
OPPORTUNITY TO SHARE WORK THAT
OUR GROUP HAS BEEN DOING OVER
THE LAST FIVE YEARS FOCUSED ON
MITOCHONDRIA AND HOW DYSFUNCTION
CAN LEAD TO NEURODEGENERATION
AND HOW THE CELERY SP CELL RESPO
DAMAGED MITOCHONDRIA.
THESE ARE MY DISCLOSURES, THAT I
WON'T BE TALKING ABOUT TODAY.
IT'S NOT PERHAPS SURPRISING THAT
MITOCHONDRIAL FUNCTION CAN BE A
DRIVER OF NEURODEGENERATION
GIVEN THAT THE NEURONS AND
MYOSITES HAVE VERY HIGH RG
DEMANDS.
THE WAY THEY'RE ABLE TO DO THAT
IS THROUGH THESE MITOCHONDRIA
THAT CAN PROVIDE ATP IN ORDER TO
MAINTAIN THOSE CONTRACTIONS.
THESE MITOCHONDRIA HAVE TO NOT
ONLY BE PROPERLY FUNCTIONING BUT
THEY ALSO HAVE TO BE PROPERLY
SHAPED AND DISTRIBUTED IN THE
TISSUE TO MEET THAT ENERGY
DEMAND.
SIMILARLY IF YOU THINK ABOUT THE
NEURONS, SPINAL CORD AND
ELSEWHERE, THEY HAVE VERY HIGH
LOCAL DEMANDS FOR ATP SUCH AS AT
THE SNAPS HERE.
SYNAPSE HERE.THESE ARE ALSO MITD
TEND TO ACCUMULATE MITOCHONDRIAL
DAMAGE OVER THE NORMAL COURSE OF
AGING, TO A GREATER EXTENT THAN
MITOTIC CELLS THROUGH CELL
DIVISION.
THESE CELLS ESPECIALLY ARE
DEPENDENT ON MECHANISMS THAT
ALLOW THE CELL TO BE ABLE TO
RECOGNIZE WHEN MITOCHONDRIAL
DAMAGE HAS OCCURRED AND TO BE
ABLE TO RESPOND TO THAT
MITOCHONDRIAL DAMAGE.
YOU MIGHT IMAGINE A COUPLE OF
DIFFERENT STRATEGIES THAT THE
CELL MIGHT USE.
ONE MIGHT BE TO ALLOW THE CHANGE
IN MITOCHONDRIA TO LEAD TO A
CHANGE IN THE OVERALL CELLULAR
STATE AND THEN SINCE THAT CHANGE
IN CELLULAR STATE -- THIS SEEMS
TO BE HOW THE CELE CELL RESPONDH
AS IN ATP THAT ARE VERY
DEPENDENT ON MITOCHONDRIAL
FUNCTION IN THE CELL.
YOU MIGHT IMAGINE THAT THERE
MIGHT BE ANOTHER STRATEGY,
THOUGH, IF THERE'S A SENSOR OF
THAT MITOCHONDRIAL DAMAGE WITHIN
THE MITOCHONDRIA ITSELF, THAT
MIGHT SERVE AS A WAY OF
RECOGNIZING WHEN THAT BECOMES
DAMAGED AND ALLOW THE CELL TO
RESPOND TO THAT DAMAGE, CONTAIN
IT BEFORE IT LEADS TO A CHANGE
IN THE OVERALL CELLULAR STATE.
BUT THERE ARE MECHANISMS THAT
ARE ABLE TO DO THIS, PERHAPS THE
BEST DESCRIBED ONE OF WHICH IS
THIS PINK1 PARKIN AUTOPHAGY
PATHWAY.
THE WAY THIS PATHWAY WORKS IS MY
TMITOCHONDRIA UNDERGOES SOME SOT
OF DAMAGE, NORMALLY IMPORTED TO
THE -- IF THAT MITOCHONDRIA IS
DAMAGED AND IMPORT PATH IS
BLOCKED THEN PINK1 ACCUMULATES
INSTEAD ON THE OUTER.
PINK1 IS A KINASE AND IT WILL
ACTIVATE PARKIN, WHICH WILL THEN
EU BIC TI NATE PROTEINS ON THE
OUTER MEMBRANE.
THIS SERVES AS A WAY OF MARKING
THIS DAMAGED MITOCHONDRION AND
DELIVERY TO A LYSOSOME WHERE IT
CAN BE DEGRADED.
THIS ACTS AS A CLEAN-UP PATHWAY
FOR DAMAGED MITOCHONDRION IN THE
CELL AND BECAUSE RECESSIVE
MUTATIONS ARE THE LEADING
GENETIC CAUSE OF EARLY ONSET
PARKINSON'S DISEASE, IT ALSO
IMPLICATES THIS MITOCHONDRIA
CONTROL PATHWAY IN PARKINSON'S
AS WELL AS OTHER FORMS OF KNEW
OWE DEGENERATION.
IN ADDITION TO THIS MI TO HAVE
-- INTO THEHEALTHY MITOCHONDRIE
CELL.
MITOCHONDRIA NORMALLY UNDERGO
THESE SI CYCLES OF FUSION AND
DIVISION AND THESE ARE MEDIATED
BY A SET OF GTP ACES ON THE
OUTER MEMBRANE, YOU GET FUSION
OF THAT MEMBRANE AND THE INNER
MEMBRANE IS MEDIATED BY FEW
SHON -- IS MADE BY OMA1 THEN THE
MY TOE COULMITOCHONDRIA -- CALLT
ALLOWS THAT MITOCHONDRIA TO
SPLIT AGAIN.
THROUGH THESE CYCLES OF FUSION
AND DIVISION THE CELL IS ABLE TO
CHANGE THE SHAPE OF THE
MITOCHONDRIAL NETWORK DYNAMIC
FULLY IN RESPONSE TO CERTAIN
DEVELOPMENTAL OR METABOLIC
QUEUES AND IT ALSO ALLOWS THE
CELL TO MAINTAIN QUALITY OF THE
OVERALL MITOCHONDRIAL -- BUT IF
THE M MITOCHONDRION UNDERGOES
DAMAGE YOU DON'T WANT TO FUSE
ANYMORE, IT DEGRADES THESE
FUSION PROTEINS ON THE OUTER
MEMBRANE, THEN CLEAVES THE
OMA1 FROM THE INNER MEMBRANE.
IT DOES THIS THROUGH AT LEAST
TWO DIFFERENT MECHANISMS.
ONE DEPENDS ON THE PINK1 PARKIN
PATHWAY ON THE OUTER MEMBRANE,
AND EVEN AT LOW LEVELS OF PARKIN
YOU'LL SEE UBIQUINIATION AND
DEGRADATION.
THERE'S A PARALLEL PATHWAY THAT
OCCURS ON THE INNER MEMBRANE OF
THE MITOCHONDRION, WHERE INSTEAD
OF PINK1 ACTING AS THE SENSOR OF
MITOCHONDRIAL DAMAGE, YOU HAVE
OMA1 WHICH IS ABLE TO SENSE
DAMAGE OF THIS INNER MEMBRANE.
IT BECOMES MORE ACTIVE AND WILL
CLEAVE THE LONG FORM OF OPA1 TO
SHORT FORM.
THE SHORT FORM OF OPA1 CAN'T
MEDIATE FUSION ON ITS OWN SO
THIS INHIBITS FUSION SO YOU HAVE
THESE TWO DIFFERENT SENSORS OF
MITOCHONDRIAL DAMAGE, PINK1
WORKING ON THE OUTER MEMBRANE
AND ONE THAT WORKS ON THE INNER
MEMBRANE.
THE OVERALL INTEREST OF OUR
RESEARCH GROUP IS TO TRY TO
UNDERSTAND THESE MECHANISMS OF
CELL SENSING OF MITOCHONDRIAL
DAMAGE AND THE ROLE THEY PLAY IN
NEURODEGENERATION AND HOW THEY
MIGHT BE MODULATED TO HELP TREAT
NANEURODEGENERATIVE DISORDERS.
OUR LAB FOCUS ON THIS PINK1
PARKIN PATHWAY AS SENSOR OF THE
DAMAGE AND ITS ROLE IN
PARKINSON'S DISEASE, AND THE
SECOND IS TO REALLY FOCUS ON
THIS OMA1 PATHWAY THAT WE FOUND
IS VERY STRONGLY ACTIVATED BY
MUTATIONS IN TWO OTHER
MITOCHONDRIAL PROTEINS THAT LEAD
TO DIFFERENT FORMS OF
NEURODEGENERATION.
AND THEN THE FOCUS OF TODAY'S
TALK WILL BE ON A SPECIFIC
MUTATION, CHCHD10 AND HOW THAT
PARTICULAR MUTATION HAS LED US
TO RECOGNIZE THE IMPORTANCE OF
THIS OMA1 STRESS RESPONSE,
PARTICULARLY IN VIVO.
SO I'LL TELL YOU -- INTRODUCE
THIS PROTEIN A LITTLE BIT MORE,
THEY'RE SMALL PROTEINS WITHIN
THE INTERMEMBRANE SPACE OF THE
MITOCHONDRIA.
SO MITOCHONDRIA HAVE THIS OUTER
MEMBRANE AS WELL AS THIS INNER
MEMBRANE AND THESE PROTEINS ARE
LOCATED BETWEEN THOSE TWO
MEMBRANES IN THE SPACE.
INNER MEMBRANE WILL ALSO FORM
MITOCHONDRIAL -- THESE PROTEINS
WILL EXTEND DOWN INTO THOSE
MITOCHONDRIAL CHRISTY AND IT
SEEMS THAT THEY'RE IMPORTED FOR
MAINTAINING NORMAL STRUCTURE AS
WELL AS FOR MAINTAINING OPTIMAL
CAPACITY OF THE MITOCHONDRIA.
WE'VE SHOWN THESE PROTEINS ARE
FUNCTIONING WITH ONE ANOTHER AND
IF YOU KNOCK OUT EITHER ALONE IN
THE MOUSE IT DOESN'T RESULT OF
MUCH OF A PHENOTYPE BUT IF YOU
FLOCK OUT BOTH OF THESE PROTEINS
TOGETHER, THE MICE DEVELOP A
CARDIOMYOPATHY.
ADDITIONALLY IF YOU LOOK IN THE
HEART TISSUE YOU SEE STRESS
RESPONSE THAT I'LL GO INTO MORE
DETAIL IN A MINUTE.
WE KNOCK OUT BOTH OF THESE
PROTEINS BUT YOU DON'T SEE IF
YOU KNOCK OUT ONLY ONE ALONE SO
THEY SEEM TO BE DOING SOMETHING
TOGETHER ON THE CELL.
DOMINANT MUTATIONS IN CHCHD10
CAUSE NEUROMUSCULAR DISORDERS.
THIS RANGES FROM DEMENTIA, ALS,
DESCRIBED WITH THE ORIGINAL
MUTATION IN THE TWO FAMILIES
THESE FAMILIES HAVE A VERY
COMPLEX NEUROLOGICAL PHENOTYPE
WHERE THEY HAVE INVOLVEMENT OF
MUSCLE AS WELL AS SPINAL CORD AS
WELL AS THE BRAIN.
THERE'S A MUCH MORE LIMITED
PHENOTYPE THAT CAN BE SEEN WITH
ANOTHER MUTATION WHERE JUST THE
LOWER MOTOR NEURONS IN THE
SPINAL CORD ARE AFFECTED,
CAUSING AN ADULT ONSET FORM OF
SPINAL MUSCULAR ATROPHY.
THIS IS RELATIVELY COMMON IN
SOUTHEAST FINLAND.
THERE'S ANOTHER MUTATION THAT'S
PROBABLY THE MOST COMMON CHCHD10
MUTATION IN NORTH AMERICA WHERE
IT CAUSES MORE OF A TYPICAL ALS
PHENOTYPE, ALTHOUGH THESE
PATIENTS ARE SLOWLY PROGRESSIVE.
IN COLLABORATION WITH NCATS WHO
IDENTIFIED THIS MUTATION, WE ARE
DEVELOPING AN ANTI -- TO TRY TO
TREAT THIS FORM OF ALS.
WE SAW A COUPLE OF PATIENTS WITH
THIS FORM OF ALS IN THE CLINICAL
CENTER EARLIER THIS YEAR.
THEN THERE'S ANOTHER MUTATION
WHERE THE INDIVIDUALS WILL
DEVELOP JUST A DOMINANT FORM OF
MYOPATHY AND AS I'LL SHOW YOU IN
A SECOND ALSO CARDIOMYOPATHY BUT
THEY DON'T SEEM TO HAVE MOTOR
NEURONS, THE SPINAL CORD SEEMS
TO BE SPARED.
IT'S INTERESTING CAN YOU HAVE
TWO MUTATIONS THAT ARE NEXT TO
EACH OTHER THAT CAN HAVE VERY
DIFFERENT PHENOTYPIC
MANIFESTATIONS.
ONE THING THAT HAD BEEN UNCLEAR
IN THE FIELD WAS EXACTLY WHICH
MUTATION IS THE CAUSE OF THE
MUTATION FOR THIS DOMINANT FORM
OF MYOPATHY.
THE REASON THAT WAS UNCLEAR IS
THAT ALTHOUGH -- IN THE LAB AT
NORTHWESTERN WAS ABLE TO
IDENTIFY CHCHD10 AS THE
CAUSATIVE GENE BY POSITIONAL
CLONING, THEY FOUND OUT ONE
VARIANT BUT ACTUALLY TWO
VARIANTS.
SO THEY COULDN'T SAY BASED ON
GENETIC GROUNDS ALONE FROM THIS
ONE FAMILY THESE TWO MUTATIONS
WAS THE CAUSE OF THE MUTATION.
SO THIS WAS IN THE BACK OF MY
MIND WHEN I MET JEFF AT A
CONFERENCE A FEW YEARS AGO WHO'S
AN EXPERT IN MITOCHONDRIAL
DISORDERS AT OXFORD.
SHE MENTIONED SHE'D BEEN
FOLLOWING FOR A NUMBER OF YEARS
A FAMILY THAT HAD A FORM OF
CARDIOMYOPATHY AND THEY RECENTLY
HAD DONE SEQUENCING AND
IDENTIFIED THIS MUTATION IN
CHCHD10 WITHOUT THE OTHER
MUTATIONS.
SO THIS WAS QUITE INTERESTING
BECAUSE IT SUGGESTS THAT THIS IS
PROBABLY THE CAUSE OF THE
MUTATION FOR THIS DOMINANT FORM
OF MYOPATHIES AND WE RESOLVED TO
HELP CHARACTERIZE THIS TOGETHER
AS PART OF THE COOPERATION.
SO THIS IS SEEN AT 8 YEARS OLD,
DISTAL AND PROXIMAL MUSCLE
WASTING, ALSO SOME MILD FACIAL
LUPUS.
THIS IS HIM 12 YEARS LATER, AND
AT THIS POINT HE'S HAD
PROGRESSION OF THE MYOPATHY,
WHEELCHAIR-BOUND.
HE ALSO DEVELOPED A
CARDIOMYOPATHY SEVERE ENOUGH TO
REQUIRE A HEART TRANSPLANT.
UNFORTUNATELY BECAUSE OF THE
IMMUNOSUPPRESSION, HE DEVELOPED
LYMPHOMA AND PASSED AWAY.
THIS IS HIS FAMILY, HIS MOTHER
HAD A VERY SIMILAR PHENOTYPE AND
ALSO DIED YOUNG, AT THE AGE OF
34, AND WE THINK THAT MOST
LIKELY THIS WAS DUE TO A
MUTATION IN HIS MOTHER.
AT THIS POINT, PH.D. STUDENT IN
THE LAB WAS INTERESTED IN TRYING
TO BETTER UNDERSTAND THE
PATHOGENESIS OF THIS DISORDER,
SO WITH THE HELP OF NHLBI
TRANSGENICS HE MADE A KNOCK-IN
MOUSE MODEL WHERE HE INTRODUCED
INTO THE MOUSE A GENE THAT WAS
SEEN IN THE PATIENT.
THESE HETEROZYGOUS MICE,
DEVELOPED A PHENOTYPE THAT LOOKS
VERY SIMILAR TO THE PATIENT'S
PHENOTYPE, DECREASED SIZE AND
WEIGHT, ALSO DECREASED STRENGTH
AND MYOPATHY AND DECREASED HEART
FUNCTION ON ECHO CARDIOGRAPHY.
NOTABLY THIS PHENOTYPE IS
DIFFERENT THAN WHAT WE HAD SEEN
AND REPORTED FOR THE SINGLE
KNOCKOUT MICE AS WELL AS THE
DOUBLE KNOCKOUT MICE.
AND THIS INDICATES THAT THIS
MUTATION IS PROBABLY CAUSING
DISEASE BY GAIN OF FUNCTION MOST
LIKELY A TOXIC GAIN OF FUNCTION
MECHANISM.
IT ALSO HAS IMPLICATIONS FOR HOW
WE'RE THINKING ABOUT TREATING
THIS DISORDER BECAUSE IT MEANS
IF YOU COULD LOWER LEVELS OF
THIS TOXIC PROTEIN IT PROBABLY
WOULD HAVE A THERAPEUTIC BENEFIT
AND THE FACT THAT IT SEEMS TO BE
TOLERATED AT LEAST IN MICE
SUGGESTS THAT YOU CAN SAFELY
LOWER EVEN -- LEVELS OF CHCHD10
AND NOS HAVE A TOXICITY RESULT.
WHAT HAPPENS TO THIS PROTEIN
WHEN IT HAS THIS MUTATION, IT
TENDS TO FORM FOCI, HEART MUSCLE
SHOWN HERE, AND WE THINK THAT
THESE FO FOCI ARE AGGREGATES OF0
PROTEINS ACTUALLY LOCATED WITHIN
THE MITOCHONDRIA.
ALSO LOOKED AT NEIGHBORING
MUTATION IN CHCHD10 AND OTHER
KNOCK-IN MOUSE MODEL.
THIS HAD BEEN PREVIOUSLY
REPORTED TO ALSO HAVING A GATS
TO HAVING AGATS THAT FORM IN THT
MUSCLE.
AGGREGATES WITH BOTH OF THESE
MUTATIONS ARE DIFFERENT
MORPHOLOGICALLY SO WITH THE G15R
MUTATION THAT CAUSES THE SEVERE
MYOPATHY, YOU HAVE THESE
PUNCTATE-LIKE AGGREGATES WHEREAS
YOU HAVE A DIFFERENT FORM OF
AGGREGATE WITH A MILDER FORM OF
MUSCLE INVOLVEMENT AND MORE
SEVERE INVOLVEMENT OF MOTOR
NEURONS.
THE LOCALIZATION OF THESE
AGGREGATES ALSO APPEARS TO BE
DIFFERENT.
SO WE CAN SEE THE BORDERS OF THE
MITOCHONDRIA BY STAINING.
THIS IS WHAT THEY LOOK LIKE IN
THE HEALTHY WILD TYPE CONDITION,
G58R, MAGENTA FOCI ARE LOCATED
PREDOMINANTLY WITHIN THE
MITOCHONDRIA, THE OTHERS ARE OUT
OF THE MITOCHONDRIA.
SO WHAT IS COMMON IS THEY'RE
TOSSING C10 TO MISFOLD BUT
PROBABLY IT FIST FOLDS INTO
DIFFERENT TOXIC SPECIES AND
PERHAPS THAT UNDERLIES THE
DIFFERENT TISSUE VULNERABILITY
TO THESE TOXIC PROTEINS.
IT SEEMS THAT MISFOLDING OF
CHCHD10 IS RELATED TO THESE TWO
PROTEINS.
TWO AUTOPSY CASES HAVE BEEN
REPORTED, AND WHEN THEY LOOK IN
THE AFFECTED REGION SUCH AS
SUBSTANTIA NIGRA, INDICATING
PROBABLY THIS PROTEIN IS
MISFOLDING ALSO BECAUSE OF THIS
MUTATION.
SIMILARLY IN A CASE OF ALS
THAT'S BEEN REPORTED DUE TO
MUTATION IN CHCHD10, IN THE
MOTOR NEURONS THAT ARE SURVIVING
IN THE SPINAL CORD, YOU'LL
FINDING A GATS OF CHCHD10 WITHIN
THOSE MOTOR NEURONS THAT AREN'T
TYPICALLY SEEN IN SPORADIC ALS.
WE ALSO LOOKED ULTRA
STRUCTURALLY AT THE MITOCHONDRIA
TO SEE HOW THEY WERE AFFECTED BY
THIS PROTEIN IN THE CENTER
MEMBRANE SPACE.
THE CHRISTY BEING VERY DISTORTED
AS WELL AS THESE INTRACRYSTAL
VESICLES THAT DEVELOP, SO WE
THINK THIS MISFOLDED PROTEIN IS
EXERTED STRESS ON THE INNER
MEMBRANE -- MEMBRANE.
AND IS LEADING TO WHAT'S
ESSENTIALLY CHRISTYOPATHY, AND
THE MILD DEFECTS WE SEE IN THE
AFFECTED TISSUES ARE PROBABLY
SECONDARY TO DAMAGE TO THIS
INNER MEMBRANE.
WE ALSO LOOKED AT THE OVERALL
MORPHOLOGY OF THE MITOCHONDRIA
IN THE HEART, USING A TECHNIQUE
CALLED FIB SYN, THEY'RE
PSEUDOCOLORRED AND YOU CAN SEE
THE INDIVIDUAL MITOCHONDRIA, AND
IF WE COMPARE THE CONTROL
CONDITION AND WE FIND THE
MITOCHONDRIA AND HEART ARE
FRAGMENTED COMPARED TO THE
CONTROL CONDITION AND OVERALL
THE VOLUME OF THE MITOCHONDRIA
IS ABOUT HALF OF WHAT WE SEE IN
THE WILD TYPE CONDITION.
SO THIS MITOCHONDRIAL
FRAGMENTATION WAS REALLY
DRAMATIC AND MADE US WONDER IF
THIS MIGHT BE A -- PROCESS AND
IN PARTICULAR IF IT MIGHT BE
INDICATIVE OF THAT STRESS
RESPONSE I INTRODUCED TO YOU AT
THE BEGINNING WHEREBY
DISRUPTIONS TO MEMBRANE --
IDENTIFY THE INNER MEMBRANES ARE
DISTORTED DUE TO THE PROTEIN
MISFOLDING IN THE CHRISTY, TO
ACTIVATED TO CLEAVE THE LONG
FORMS TO THE SHORT FORMS.
IF YOU INHIBIT FUSION
FRAGMENTATION OF THE
MITOCHONDRIAL NETWORKS.
SO WE LOOKED AT OMA1 PROCESSING
OF THE SPECIFIC OMA1, THE C AND
E SHOWN IN THIS WESTERN BLOT
WITH THE AFFECTED TISSUES.
SIM SKELETAL MUSCLE, HEART
TISSUE, WE SAW THE SAME PATTERN
INDICATIVE OF OMA1 ACTIVATION.
SO WE HAVE THIS OMA1 STRESS
RESPONSE ACTIVATED BY THIS
PROTEIN THAT'S MISFOLDING WITHIN
MITOCHONDRIAL CRISTAE.
SO WHILE WE WERE DOING THIS
WORK, A COUPLE OF VERY
INTERESTING PAPERS CAME OUT, ONE
FROM UCSF AND ANOTHER IN MUNICH.
WHAT THEY FOUND IS THAT AT LEAST
IN CULTURED CELLS THAT ARE
EXPOSED TO MITOCHONDRIAL TOXINS
LIKE CCP AND -- OPA1 HAS ANOTHER
SUBSTRATE IN ADDITION TO
OPA1 CALLED DELI1.
IT COMMUNICATES THE M
MITOCHONDRIAL SUPPRESS BY
OMA1 TO THE CYTOSOL NUCLEUS TO
SOMETHING CALLED THE INTEGRATED
STRESS RESPONSE.
SPECIFICALLY OMA1 WILL CLEAVE
THE LONG FORM OF DELE1 INTO A
SHORT FORM THAT WILL THEN
ACTIVATE THIS EIFT ALPHA CLIE
NAIS.
WHEN THIS EIF2L ALPHA IS
PHOSPHORYLATED, THIS TRANSLATION
INITIATION FACTOR IS GOING TO
LEAD TO THE INTEGRATED STRESS
RESPONSE THAT HAS TWO MAIN
COMPONENTS.
THE FIRST IS TO PUT A HALT ON
MOST PROTEIN TRANSLATION SO YOU
GET DECROSED PROTEIN SYNTHESIS
OVERALL IN THE CELL.
BUT THEN CERTAIN TRANSCRIPTION
FACTORS LIKE ATF4 AND 5 THAT
HAVE THESE SPECIAL UPSTREAM --
ARE PREFERENTIALLY TRANSLATED AS
YOU HAVE UPREGULATION OF THESE
THAT CAN MEDIATE A
TRANSCRIPTIONAL RESPONSE.
IT'S CALLED THE INTEGRATED
STRESS RESPONSE BECAUSE THERE
ARE ACTUALLY FOUR DIFFERENT
KINASES, EACH OF WHICH -- FOR
INSTANCE, PERC AND EACH WILL
PHOSPHORYLATE THE SAME RESIDUE
LEADING TO THIS STEREOTYPED
RESPONSE TO A VARIETY OF
DIFFERENT CELLULAR STRESS.
SO THIS HAD BEEN DEMONSTRATED
VERY NICELY IN CULTURED CELLS
BUT WE WONDERED CAN THIS
ACTUALLY OCCUR IN VIVO IN A
DISEASE RELEVANT MODEL SYSTEM.
WE THOUGHT WE HAD A GOOD MODEL
SYSTEM TO POTENTIALLY TEST THIS
IDEA.
SO WE FIRST ASKED IS THIS
INTEGRATED STRESS RESPONSE
ACTIVATED IN AFFECTED TISSUES OF
OUR MOUSE MODEL.
INDEED WE FOUND EIF2 ALPHA IS
PHOSPHORYLATED BOTH IN THE HEART
AND THE AFFECTED SKELETAL
MUSCLE.
WE NEXT ASKED IS THIS BEING
SIGNALED BY OMA1 AND TO GET AT
THIS QUESTION, WE KNOCKED DOWN
OMA1 IN VIVO BY INJECTING THE
ANIMALS AGAINST OMA1, WE
ACHIEVED VERY GOOD KNOCK DOWN AT
THE PROTEIN LEVEL IN THE HEART
AND THIS SUPPRESSED THIS
ACTIVATION OF THE INTEGRATED
STRESS RESPONSE, INDICATING THAT
IT IS BEING SIGNALED BY OMA1 IN
VIVO.
WE SAW VERY CONSISTENT RESPONSE
IN THE TRANSCRIPTOMICS, WE SEE
UPREGULATION IN THE -- HEARTS
COMPARED TO THE WILD TYPE BUT
TRANSCRIPTION FACTOR IS KNOWN TO
BE PART OF -- AS WELL AS A
NUMBER OF DOWNSTREAM TARGETS.
IF WE LOOK AT MUTED HEARTS WE
GET DOWN RG LAITION OF THE SAME
TRANSCRIPTIONAL SIGNATURE
INDICATING THAT.
OMA1 IS
RESPONSIBLE IN MUTED HEARTS.
WE NEXT ASKED IS THIS RESPONSE
PROTECTIVE OR DETRIMENTAL TO
THESE ANIMALS?
WE CROSSED OUR CROSSED ANIMAL
WITH -- WHAT WE FOUND IS IF THEY
CAN'T TURN ON THE STRESS
RESPONSE MOST OF THE MICE WILL
DIE IN THE FIRST EIGHT DAYS OF
LIFE.
ABOUT A THIRD OF THEM CAN
SURVIVE LONGER, TO ABOUT 14 OR
15 WEEKS, BUT THOSE ANIMALS HAVE
THESE MASSIVELY ENLARGED HEARTS.
SO WE THINK THAT THIS STRESS
RESPONSE IS HELPING THE CELL AND
THE TISSUE COPE WITH THE
MITOCHONDRIAL DAMAGE THAT'S
BEING CAUSED BY THIS PROTEIN
MISFOLDING WITHIN THE
MITOCHONDRIAL CRISTAE.
SO TO PUT THIS TOGETHER, WE HAVE
THIS PROTEIN MISFOLDING WITHIN
THE MITOCHONDRIAL -- AND IT'S
ACTIVATING THIS TRANSCRIPTIONAL
RESPONSE THAT LEADS TO A NUMBER
OF METABOLIC CHANGES INCLUDING
UPREGULATION OF PATHWAYS
INVOLVED IN -- SYNTHESIS AND
CARBON METABOLISM AND IS BEING
SIGNALED BY OMA1 AND DELE1.
THIS RAISES THE QUESTION, IS
THIS A VERY GENERAL RESPONSE, IS
IT ALSO SIGNALING OTHER FORMS OF
MITOCHONDRIAL STRESS IN THE
HEART AND OTHER ORGANS.
AND A COUPLE OF PAPERS THAT HAVE
BEEN PUBLISHED SINCE WE
PUBLISHED THIS FINDING SUGGESTS
THIS IS PROBABLY A MAJOR
RESPONSE TO DIFFERENT FORMS OF
MITOCHONDRIAL STRESS.
THERE WAS A PAPER WHICH
DEMONSTRATED THAT IF YOU INHIBIT
CARDIO -- THERE IS IMPORTANT FOR
THE INNER MEMBRANE OF
MITOCHONDRIA WITH KNOCKOUTS OF
EITHER OF THESE TWO PROTEINS YOU
GET VERY SIMILAR TRANSCRIPTIONAL
RESPONSE.
THIS IS DEPENDENT ON THE -- AS
WELL AS PHOSPHORYLATION AND VERY
RECENTLY IT WAS DEMONSTRATED IF
YOU CREATE DEFICIENCY IN THE
HEART BY KNOCKING OUT THE
SUBUNIT OF THE OXPHOS CHAIN ON
COX10, YOU GET A VERY SIMILAR
TRANSCRIPTIONAL RESPONSE,
SIMILARLY DEPENDENT ON DELE SO
WE THINK THIS IS GOING TO TURN
OUT TO BE PREDOMINANTLY -- IN
VIVO ORGANISMS.
SO TO SUMMARIZE OUR FINDINGS, WE
HAVE MUTATIONS IN C2 AND C10
THAT CAUSE NEUROTEE GENERATIVE
DISORDERS WITH A CLEAR
GENOTYPE-PHENOTYPE RELATION SHI.
DOMINANT MUTATIONS IN C2 AND C10
CAUSES PROTEINS TO MISFOLD AND
LICELY -- THE CHCHD2 -- LEADS TO
MITOCHONDRIAL MYOPATHIES AND
STRESS RESPONSE WITH LOCAL AND
GLOBAL RESPONSES THAT PROTECT
FROM MITOCHONDRIAL DAMAGE.
I JUST WANT TO ACKNOWLEDGE A --
BIOLOGIST AND LAB MANAGER WITHIN
THE LAB.
AND WITH THAT, I'LL TURN IT OVER
NOW TO CLAIRE, WHO WILL TELL BUT
A DIFFERENT STRESS RESPONSE.
>>THANKS, DEREK, AND THANK YOU,
TOM, FOR THE NICE INTRODUCTION.
SO TODAY I'M GOING TO TELL YOU
ABOUT SOME OTHER TYPES --
ADDITIONAL TYPES OF STRESS
RESPONSES THAT WE THINK ARE
IMPORTANT IN THE CONTEXT OF
NEURODEGENERATION.
AND THOSE ARE AXON INJURY
RESPONSES.
AND SO IN MY LAB, IN NICHD,
WE'RE REALLY INTERESTED IN HOW
NEURONS RESPOND TO INJURY BY
SPECIFIC STRESS RESPONSES IN
PARTICULAR, AXON INJURY
RESPONSES.
I DO THINK THIS WORK WILL HELP
US BETTER UNDERSTAND THE
PATHOPHYSIOLOGY OF
NEURODEGENERATIVE DISEASE, SO
TODAY I'M GOING TO SHOW YOU A
BRIEF INTRODUCTION ON ONE OF THE
PATHWAYS THAT WE FOCUS ON, AND
THEN SHARE WITH YOU THREE
VIGNETTES OF WORK THAT WE HAVE
DONE IN MY LAB TO KIND OF
ILLUSTRATE THIS IDEA.
JUST TO SHOW THAT I HAVE NO
DISCLOSURES, AND TODAY IF THERE
IS A LEARNING OBJECTIVE, I'D
LIKE TO CONVINCE YOU THAT AXON
DAMAGE SIGNALING IS A TYPE OF
NEURONAL STRESS THAT'S RELEVANT
TO MANY CONDITIONS THAT INVOLVE
NEURODEGENERATION, INCLUDING
SEVERAL DISEASES, STROKE,
TRAUMATIC INJURIES TO THE BRAIN
AS WELL.
AND IN MY LAB, WE USE DIFFERENT
TYPES OF MODELS, INCLUDING THE
TYPES OF PRECISION MOUSE MODELS
OF DISEASE THAT YOU HEARD FROM
DEREK.
I'M NOT GOING TO TALK ABOUT
THOSE TODAY.
WE ALSO HAVE MOUSE MODELS OF
TRAUMATIC NERVE INJURY AND BRAIN
INJURY, AND WE TRY TO LEVERAGE
SINGLE CELL SEQUENCING
TECHNOLOGY TO STUDY DIFFERENTIAL
AND CELL TYPE-SPECIFIC RESPONSES
TO INJURY AND DISEASE, AS WELL
AS WE HAVE STARTED USING HUMAN
IPSC-DERIVED NEURONS TO
TRANSLATE AND HAVE A TRACTABLE
SYSTEM FOR CELL BIOLOGICAL
STUDIES.
OKAY.
SO IN VERY SIMPLE TERMS,
NEURODEGENERATION CAN BE CAUSED
BY A COMBINATION OF GENETIC
PREDISPOSITION AS WELL AS
ENVIRONMENTAL FACTORS
EXPERIENCED DURING DEVELOPMENT
AND IN THE LIFESPAN.
IN MY LAB, WE'RE PARTICULARLY
INTERESTED IN THE COMMON
DOWNSTREAM PATHWAYS THAT LEAD TO
NEURODEGENERATION.
IN PARTICULAR, ONE OF THE
PATHWAYS THAT WE FOCUSED ON
QUITE A LOT SINCE I STARTED
WORKING ON THIS WHEN I WAS AT
GENENTECH IS DLK, AND MAPP.
MAP3K12.THE IDEA IS IF WE CAN TT
PATHWAYS LIKE THIS THAT ARE
RELATIVELY I WOULD SAY A
DOWNSTREAM PROCESS IN THE
CONTEXT OF, YOU KNOW, THE STEPS
LEADING TOWARDS LOSS OF NEURONS,
THEN THIS COULD BE A POTENTIALLY
VALUABLE WAY TO PREVENT NEURONAL
CELL DEATH IN THE CONTEXT OF
MANY DIFFERENT DISEASES.
SO HOW WE CAME TO STUDY THIS WAS
ACTUALLY THANKS TO THE FINDINGS
THAT MY COLLEAGUES HAD MADE AT
GENENTECH, WHICH IS THAT DLK IS
ACTUALLY REALLY IMPORTANT IN
DRIVING A PARTICULAR KIND OF
NEURONAL CELL DEATH THAT HAPPENS
DURING DEVELOPMENT, WHICH IS A
NORMAL AND HEALTHY PROCESS.
SO HERE I'M SHOW YOU ING YOU AN
EXAMPLE.
THESE ARE -- THE GREEN CELLS,
THE GREEN CELLS ARE MOTOR NEURON
NUCLEI FROM THE SPINAL CORD OF A
DEVELOPING MOUSE, AND YOU CAN
SEE THAT THERE ARE MANY MORE OF
THEM, EMBRYONIC DATA --
BASICALLY DLK IS RESPONSIBLE FOR
A WAVE OF NEURONAL CELL DEATH
THAT OCCURS DURING DEVELOPMENT
AS SHOWN HERE IN A KNOCKOUT
ANIMAL, THIS FAILS TO OCCUR.
AND SO THE VERY SIMPLE QUESTION
WE ASKED WAS, WELL, IF THIS
HAPPENS DURING NORMAL
DEVELOPMENT AND DLK SIGNALS THE
CELLS TO DIE, COULD THIS PATHWAY
POTENTIALLY BE ACTIVATED AGAIN
IN THE CONTEXT OF DISEASE IN A
MATURE ORGANISM?
SO TO DO THIS, I CROSSED A MOUSE
MODEL OF, IN THIS CASE, ALS, SO
IT'S A MOUSE THAT OVEREXPRESSES
A MUTANT VERSION OF THE GENE
THAT CAUSES EARLY ONSET ALS.
AND SO YOU CAN SEE THAT IN
THIS -- THE MOUSE MODEL FOR THIS
DISEASE, THE MOTOR NEURONS THAT
ARE LABELS BY THIS TRANS IF HE
RACE STAIN ARE LOST.
I CROSSED THESE MICE TO
INDUCIBLE KNOCKOUTS OF DLK, SO
THAT WE COULD BLOCK DLK
SIGNALING IN THE MATURE
ORGANISM.
AND YOU CAN SEE HERE THAT THIS
WAS ACTUALLY QUITE POWERFUL IN
TERMS OF PREVENTING THESE CELLS
FROM DYING.
SO A LOT OF BASIC RESEARCH HAS
UNCOVERED REALLY INTERESTING
ASPECTS OF DLK SIGNALING, AND
I'M GOING TO TRY TO SUMMARIZE
THOSE IN THE FOLLOWING SLIDES.
AND IT TURNS OUT THAT IN THE
COURSE EVER THESE STUDIES, ONE
OF THE BEST WAYS TO ACTIVATE DLK
IS ACTUALLY BY INJURING THE
AXON.
SO IF YOU CAUSE AXON DAMAGE, YOU
CAN TU TURN THE PATHWAY ON.
WE LIKE TO USE THIS, THERE'S A L
TO STUDY THE MODEL AND TO DRIVE
IT.
SO HERE'S THE SUMMARY.
AXON DAMAGE CAN CAUSE THE
ACTIVATION OF DLK, WHICH AS I
MENTIONED EARLIER IS A MAP
TRIPLE KINASE, RESPONSIBLE FOR
PHOSPHORYLATING DOWNSTREAM
SUBSTRATES.
AND WHEN I SAY AXON INJURY, AND
HERE'S KIND OF THE RELEVANCE TO
NEURODEGENERATION THAT I HOPE TO
GET ACROSS TODAY, IT'S NOT
SIMPLY MECHANICAL INJURY OF AN
AXON, BUT I MEAN THIS IN A VERY
WIDE SENSE, SO WE CAN HAVE
MECHANICAL INJURY, YOU COULD
HAVE THE TYPES OF STRESSES THAT
DEREK WAS TALKING ABOUT THAT
MIGHT BE UPSTREAM OF THIS AXON
TRANSPORT DISRUPTION AND
PROTEOTOXIC STRESS.
BECAUSE FOR EXAMPLE, IN A MOUSE
MODEL OF ALS THAT I SHOWED YOU,
THOSE ANIMALS ARE NOT UNDERGOING
MECHANICAL INJURY, BUT SOME
OTHER TRIGGER.
SO THIS KINASE PHOSPHORYLATION
SETS OFF THIS RETROGRADE SIGNAL
THAT CAN RESULT IN A
TRANSCRIPTIONAL RESPONSE SO WE
HAVE AN UPREGULATION OF
TRANSCRIPTION FACTORS AND THE
ACTIVE FORM OF THIS
TRANSCRIPTION FACTOR WHICH IS A
PHOSPHORYLATED VERSION DIRECTLY
DOWNSTREAM OF THIS CASCADE OF
THIS KINASE CASCADE.
NOW, THAT'S THE PART OF THE CELL
THAT'S CONNECTED TO THE CELL
BODY.
AT THE OTHER END, WHAT WE CALL
THE DISTAL AXON, THIS PART OF
THE AXON UNDERGOES AXON
DEGENERATION, AND THIS INVOLVES
OTHER GENES THAT I'M NOT GOING
TO DESCRIBE TODAY FOR THE SAKE
OF TIME, BUT ONLY TO SAY THAT
DLK ALSO CONTRIBUTES TO THIS
TYPE OF WHAT'S KNOWN AT
WALLERIAN DEGENERATION.
IN ADDITION TO WHAT I'VE JUST
DESCRIBED IN TERMS OF AXON
DEGENERATION AND ACTIVATION OF A
TRANSCRIPTIONAL RESPONSE, THIS
RESPONSE CAN ACTUALLY LEAD TO
MANY DIFFERENT OUTCOMES,
INCLUDING THINGS LIKE THE NEURON
CELL DEATH THAT I DESCRIBED
EARLIER BUT ALSO IN SOME CASES
TO REPAIR AND REGENERATION.
AND THIS IS MOST NOTABLY BEEN
SHOWN IN WORMS, IN FLIES AND IN
MICE FOR PERIPHERAL NEURONS.
OKAY.
SO ONE THING MY LAB DEMONSTRATED
WAS ACTUALLY THAT IN ADDITION TO
ALL OF THESE THINGS THAT I
DESCRIBED WHICH ARE REALLY
INTRINSIC TO THE INJURED NEURON,
THIS PATHWAY CAN ALSO SIGNAL TO
THE OUTSIDE OF THE INJURED CELL,
AND IN THIS CASE, THE VIGNETTE
I'M GOING TO SHARE WITH YOU NOW
IS THAT ONE OF THE
TRANSCRIPTIONAL RESPONSES
ACTUALLY CAN DRIVE
NEUROINFLAMMATION.
SO THIS WORK WAS DONE BY THIS
TEAM IN MY LAB, AND WE PUBLISHED
THIS JUST AS A KIND OF -- TO
SITUATE YOU IN TERMS OF THE
ANATOMY I'M GOING TO BE
DESCRIBING.
SO I'M GOING TO BE TALKING ABOUT
THE SENSORY NEURONS THAT RESIDE
IN THE DORSAL ROOT GANGLIA THAT
LINE THE SPINAL CORD.
AND I'M ALSO -- SO THESE ARE THE
DRG NEURONS, AND THEIR CELL BODY
PROJECTS AN AXON WHICH
BIFURCATES AND ACTUALLY PROJECTS
TO, ON THE ONE HAND, THE DORSAL
HORN OF THE SPINAL CORD.
AND AT THE OTHER END, TO THE
PERIPHERY.
AND THEN WHEN WE DO THE TYPE OF
NERVE INJURY THAT I'M ABOUT TO
DESCRIBE, WHICH WOULD BE, FOR
EXAMPLE, CRUSHING OR CUTTING THE
SCIATIC NERVE, WE'RE ALSO
INJURING THE SPINAL MOTOR
NEURONS AND THESE PROJECT THEIR
AXON TO THE PERIPHERAL MUSCLE TO
GENERATE MUSCLE CONTRACTION.
SO WHAT I'M SHOWING YOU HERE IS
ACTUALLY A MOUSE SPINAL CORD.
THIS IS FROM AN ANIMAL WHICH HAS
RECEIVED THIS TYPE OF SCIATIC
NERVE INJURY ON THIS SIDE ONLY,
AND WE HAVE STAINED THE WHOLE
TISSUE TO REVEAL THE MICROGLIA
IN THE SPINAL CORD.
AND YOU CAN APPRECIATE THAT WE
HAVE TWO CLOUDS OF MICROGLIA.
ONE OF THEM IN THE DORSAL HORN
WHICH IS WHERE THE SENSORY
NEURONS THAT WE INJURED PROJECT
TO, AND ANOTHER ONE IN THE
VENTRAL HORN, HERE, WHICH IS
WHERE -- WHICH IS SURROUNDING
THE MOTOR NEURON CELL BODIES OF
THE CELLS -- OF THE MOTOR
NEURONS THAT WE INJURED.
AND SO WE LOOKED TO SEE, AND
HERE I'M SHOWING YOU BY THE TOP
VIEW WHAT THIS WOULD LOOK LIKE
IN AN ANIMAL THAT LACKED DLK.
SO TO MODEL BLOCKING DLK.
AND WHAT WE OBSERVED IS THAT
THIS NEUROINFLAMMATORY RESPONSE
WAS COMPLETELY PREVENTED, AND SO
JUST QUITE RAPIDLY, I JUST WANT
TO SHOW YOU EVIDENCE HERE THAT
WHAT WE UNDERSTAND NOW, HOW THIS
WORKS, IS THAT DLK DRIVES
UPREGULATION OF THIS GENE CALLED
CSF 1, WHICH IS ACTUALLY A
CYTOKINE THAT'S NOT NORMALLY
EXPRESSED IN NEURONS, AND YOU
CAN SEE THAT THE UPREGULATION OF
THIS GENE FAILS TO OCCUR IN THE
DR DP.s, RGs, FOR EXAMPLE, OF K
KNOCKOUT, SO WHAT WE THINK
HAPPENS IS THAT UPON INJURY, THE
DLK PATHWAY IS ACTIVATED, IT
UPREGULATES CSF 1 IN THE SENSORY
NEURONS AND THE MOTOR NEURONS.
BY
THIS RETROGRADE SIGNAL THAT I
DESCRIBED EARLIER, AND THEN THE
UPREGULATION OF CSF 1 AND THOSE
NEURONS CAUSES LOCAL
PROLIFERATION AND ACTIVATION OF
THE MICROGLIA, WHICH EXPRESS THE
RECEPTOR FOR THIS CYTOKINE.
AND THAT'S WHY WE HAVE TWO
CLOUDS OF MICROGLIA, HERE AND
HERE.
NOW, I'VE SHARED WITH YOU HOW
DLK STRESS SIGNALING CAN
UPREGULATE A GENE LIKE CSF 1 AND
INVOLVE GLIAL CELLS IN A
TISSUE-WIDE STRESS RESPONSE.
AND WHAT WE REALLY WANTED TO
FIGURE OUT WAS A WAY IN WHICH WE
COULD KNOW THE ENSEMBLE OF ALL
THE GENES THAT GET O UP OR DOWN
REGULATED IN INDIVIDUAL CELLS
AND WE SET OUT TO DO THIS FOR
THE SPINAL MOTOR NEURONS.
THE FIRST STEP WAS ACTUALLY JUST
TO CHARACTERIZE THE MOTOR NEURON
SUBTYPES IN THE HEALTHY ADULT
MOUSE.
AND SO FOR THIS, WE'VE USED
SINGLE CELL SEQUENCING, AND THIS
STUDY WAS PUBLISHED LAST YEAR BY
THIS TEAM OF GRADUATE STUDENTS
IN THE LAB, AND OUR ULTIMATE
GOAL WOULD BE TO USE THIS TYPE
OF PROFILING THAT I'M GOING TO
SHOW YOU TO FOLLOW
TRANSCRIPTOMIC ALTERATIONS IN
INDIVIDUAL MOTOR NEURONS DURING
DISEASE PROGRESSION OR INDEED
AFTER INJURY.
SO THE STRATEGY THAT WE EMPLOYED
WAS TO USE A MOUSE LINE IN WHICH
THE SPINAL MOTOR NEURONS ARE
LABELED BY A NUCLEAR REPORTER,
SO THESE ARE THE GREEN NUCLEI
THAT YOU'RE SEEING HERE IN THIS
CLEAR SPINAL CORD.
THIS ALLOWS US TO ENRICH FOR
THIS POPULATION WITHIN THE
SPINAL CORD BECAUSE IT'S ONLY
ABOUT 1% OF ALL OF THE NEURONS.
-- SORRY -- ALL THE CELLS IN
THE SPINAL CORD.
AND SO IF WE DON'T DO THIS, WE
FAIL TO ENRICH THIS POPULATION
ENOUGH TO SEE SUFFICIENT NUMBERS
OF THEM.
WHAT WE DID WAS WE SEPARATELY
SEQUENCED THREE REGIONS OF THE
SPINAL CORD.
SO THIS WAS OUR WORKFLOW.
WE HARVESTED THE TISSUE, WE
HOMOGENIZED THE TISSUE AND WE
ISOLATED NUCLEI THAT WE FACT
SORTED IN ORDER TO SELECT FOR
THE ONES SELECTING GFP, WHICH
AGAIN WAS UNDER THE CONTROL
OF -- BASICALLY WHICH IS ONLY
EXPRESSED IN THE CHOLINERGIC
CELLS.
AND JUST TO POINT OUT HERE THAT
WHEN WE USE THIS APPROACH, WE'RE
NOT JUST ENRICHING FOR THE
SKELETAL MOTOR NEURONS WHICH WE
WERE MOST INTERESTED IN, BUT WE
ALSO WOULD BE PURIFYING
INTERNEURONS THAT ARE
CHOLINERGIC, AS WELL AS
PREGANGLIONIC CELLS AS WELL AS
MOTOR NEURONS.
SO THE DATA LOOK LIKE THIS.
THIS IS A REPRESENTATION OF
SINGLE NUCLEUS TRANSCRIPTOMICS,
AND EACH DOT IN THIS
REPRESENTATION CORRESPONDS TO
ONE NUCLEUS OF A CHOLINERGIC
CELL THAT WE HAVE SEQUENCED.
AND THEN THE PROXIMITY OF TWO
DOTS TO ONE ANOTHER ON THIS
GRAPH REPRESENTS THEIR
TRANSCRIPTIONAL SIMILARITY, SO
THIS IS BASICALLY MAPPING A
RELATIONSHIP OF EACH CELL TO
ANOTHER USING THE FULL
REPERTOIRE OF GENES THAT ARE
DETECTED IN EACH CELL.
SO WHAT YOU CAN SEE HERE ARE
THESE CLUSTERS THAT ARE
COLOR-CODED WHICH WOULD
CORRESPOND TO THE DIFFERENT
SUBTYPES OF SPINAL CHOLINERGIC
NEURONS THAT WE DISCOVERED.
USING A COMBINATION OF A FEW
EXISTING KNOWN MARKERS AND THEN
SOME ITERATIVE LOOKING AT GENES
THEY EXPRESSED AND GOING TO SEE
IN THE TISSUE WHERE THESE WERE
LOCATED, WE DETERMINED THAT
THESE WERE THE POPULATIONS OF
SKELETAL MOTOR NEURONS AND THAT
THERE WAS QUITE A DIVERSE
POPULATION OF PREGANGLIONIC
CELLS, AND THEN THE REMAINING
ONES WE HAVE HERE ALL CORRESPOND
TO CHOLINERGIC INTERNEURONS
WHICH WAS REALLY SURPRISING
BECAUSE ONLY ONE OR TWO TYPES
HAD EVER BEEN DESCRIBED BEFORE.
SO WHAT WE CAN USE THIS KIND OF
DATA FOR IS TO QUERY IT FOR
WHICH THE TOP MARKERS OF EACH
TYPE.
SO ONE EXAMPLE I'M GOING TO SHOW
YOU HERE, ON THIS GRAPH YOU HAVE
A LIST OF GENES AND THEN THE
SIZE OF THE CIRCLE SHOWS YOU
WHAT PERCENTAGE OF THAT CELL
TYPE EXPRESSES A GIVEN GENE, SO
IN THIS CASE TNS1 WAS VERY
WIDELY EXPRESSED IN SKELETAL
MOTOR NEURONS BUT NOT IN THE
OTHER TWO TYPES, SO TNS1 WOULD
BE PREDICTED TO BE A REALLY GOOD
MARKER.
SO WHAT YOU CAN SEE HERE IS A
DIFFERENT REPRESENTATION OF TNSL
MOTOR NEURONS AND IF WE DO
HYBRIDIZATION FOR THIS GENE, YOU
CAN SEE THAT IT'S REVEALING
MOTOR NEURONS IN THE VENTRAL
HORN OF THE SPINAL CORD.
NOW WE WANTED TO FOCUS IN ON THE
ALPHA MOTOR NEURONS, WHICH ARE
THE TYPE OF MOTOR NEURON THAT
CONTROL MUSCLE CONTRACTION.
AND IF WE JUST TAKE THAT SUBSET
AND SUBCLUSTER THEM TO LOOK AT
WHAT DIFFERENT TYPES OF THEM
EXIST, WE COULD DETECT MULTIPLE
TYPES.
AND IN ORDER TO KNOW WHICH ONE
CORRESPONDED TO WHICH, WE
EMPLOYED A BACK LABELING METHOD
IN WHICH WE WOULD INJECT A
PARTICULAR MUSCLE WITH A TRASER.
THE TRASER IS TAKEN UP AND WILL
LABEL THE CELL BODY THAT WE
COULD DETECT IN THE SPINAL CORD
IN SECTIONS.
THEN WE COULD OVERLAY ON TOP OF
THIS IN SITU HYBRIDIZATION FOR
ALPHA MOTOR NEURON MARKERS AND
DIFFERENT MARKERS FOR THE
DIFFERENT SUBTYPES OF ALPHA
MOTOR NEURONS THAT WE DETECTED.
SO ONE REALLY INTERESTING THING
WE DISCOVERED WAS THAT THERE WAS
A PARTICULAR SUBTYPE THAT WAS
PRESENT ONLY IN THE CERVICAL
REGION, BUT NOT REALLY IN
THORACIC OR IN THE LUMBOSACRAL
AREA, AND WE THOUGHT THIS WOULD
BE A REALLY GOOD CANDIDATE FOR
PHRENIC MOTOR NEURONS WHICH
CONTROL THE DIE T TH THE DIAPHR,
THEREFORE, CONTROL BREATHING.
THE BEST MARKER FOR THIS CLUSTER
THAT WAS NOT EXPRESSED IN OTHER
CLUSTERS WAS THE GENE ERB4.
WE HAVE CIRCLED TWO MOTOR
NEURONS AS REVEALED BY THIS
MARKER FOR ALPHA MOTOR NEURONS
THAT WE HAD DISCOVERED AND WE
DETECTED IN THESE CELLS THAT
ERBB4, THE BEST MARKER FOR THIS
CLUSTER NUMBER 7 WAS INDEED
EXPRESSED WHEN WE HAD LABELED
PHRENIC MOTOR NEURONS USING A
TRANSTHORACIC INJECTION OF OUR
BLUE MARKER HERE.
SO IN ADDITIONAL WORK, WE KIND
OF IDENTIFIED THIS OTHER CLUSTER
AS INNOVATING DIGITS.
AND SO WHAT WE THINK HERE IS
THAT THE SUBTYPES OF ALPHA MOTOR
NEURONS WE SEE CORRESPOND TO
SPECIFIC MOTOR POOLS THAT
INNERVATE SPECIFIC TYPES OF
MUSCLES.
AND THIS IS REALLY INTERESTING
AND RELEVANT TO DISEASES SUCH AS
ALS BECAUSE THIS NEURONAL
POPULATION IS RELATIVELY
RESILIENT IN DISEASE BUT THEN
ULTIMATELY THE LOSS OF FRENK
MOTOR NEURON FUNCTION LEADS TO
THE DEATH OF THE PATIENTS.
AN INTERESTING THING TO NOTE IS
THAT RECENT STUDIES HAVE
ACTUALLY DETECTED MUTATIONS IN
THIS GENE ERBB4 AND SUGGESTED
THAT THEY COULD CAUSE ALS, AND
INTERESTINGLY, THE TYPE OF ALS
THAT THEY CAUSE IS RESPIRATORY
ONSET ALS, MEANING A TYPE OF ALS
IN WHICH THE ABILITY TO BREATHE
IS AFFECTED EARLIER AS OPPOSED
TO LIMBS BEING AFFECTED FIRST.
SO WE DEPOSITED THESE DATA HERE,
SO JUST TO SAY WE HAVE A LOT OF
ONGOING WORK IN THIS AREA IN
TERMS OF NOW APPLYING THIS
TECHNIQUE BECAUSE THIS WHOLE
STUDY WAS JUST CREATING AN ATLAS
OF HEALTHY NEURONS, AND NOW WE
WANT TO APPLY THIS IN THE
CONTEXT OF DISEASE AND AXON
DAMAGE.
SO I JUST WANT TO END ON A THIRD
LITTLE VIGNETTE OF SOME WORK
THAT WE HAVE ONGOING RIGHT NOW
IN WHICH WE ARE STUDYING THE DLK
PATHWAY BUT FOR THE FIRST TIME
IN HUMAN NEURONS, SO RELATIVELY
LITTLE IS ACTUALLY KNOWN ABOUT
HOW CONSERVED ALL OF THIS IS IN
HUMAN NEURONS.
SO THE PLATFORM THAT WE'RE USING
IS IPSC-DERIVED NEURONS, THANKS
TO OUR COLLABORATOR MICHAEL WARD
IN NINDS WHO'S PROVIDED US WITH
THIS KIND OF IPSC NEURON THAT'S
KIND OF PROGRAMMED TO EXPRESS
NEUROGENIN2, AND THIS YIELDS A
GLUTAMATERGIC TYPE OF NEURON
THAT RESEMBLES A CORTICAL
NEURON.
AND THIS WORK IS BEING LED BY A
POSTDOC IN THE LAB, JORGE GOMEZ
GOMEZ-D EEEZA.
I'M JUST GOING TO SHOW YOU AN
EXAMPLE OF A VERY EARLY TRIAL
WHERE JORGE KIND OF WAS REALLY
EXCITED TO FIND A MICROSCOPE
THAT WE COULD USE, AND TO DO
THESE EXPERIMENTS, AND HE GOT
REALLY A LITTLE OVERZEALOUS
HERE, BUT YOU CAN SEE THIS IS
HOW HE SHOOTS THE AXONS.
NOWF WE HAVE THIS KIND OF MORE
CAREFULLY CALIBRATED, BUT WE CAN
DO THIS IN A REALLY RELIABLE
MANNER, AND HE DOES THIS IN A
DISH OF VERY SPARSELY LABELED
NEURONS SO HE CAN SEE THE
ENTIRETY, THE NEURONS ARE VERY
DENSE IN THE DISH BUT HE CAN SEE
THE ENTIRETY OF ONE WHOLE NEURON
IF MAYBE ONLY A SMALL FRACTION
OF THE NEURONS IN A DISH ARE
EXPRESSING A FLUORESCENT
PROTEIN.
SO THAT'S WHAT I'M SHOWING YOU
HERE IN GRAPHICAL FORMAT.
YOU CAN ALSO IDENTIFY WHICH AXON
BELONGS TO WHICH CELL BODY IN
THIS SYSTEM, SO WE'RE VERY
INTERESTED IN NOW OBSERVING WHAT
HAPPENS IN THE AXON THAT'S
CONNECTED TO THE CELL BODY, AS I
REFERRED TO IN MY INTRODUCTION.
AND WHAT HAPPENS IS SHOWN HERE,
SO THE NEURONS ARE EXPRESSING A
CYTOPLASMIC RED FLUORESCENT
PROTEIN, AND YOU CAN SEE THAT
THE ASTERISK MARKS THE SITE OF
AXOTOMY, AND YOU CAN SEE THAT
OVER TIME, THE RED FLUORESCENCE
IS BEING LOST IN THE DIRECTION
FROM THE AXOTOMY SITE TO THE
CELL BODY.
THESE CELLS ARE ACTUALLY
UNDERGOING AXON DEGENERATION.
THIS IS INTERESTING BECAUSE IN
MOUSE NEURONS, IF YOU DOO THIS
TO DO THIS TOMOUSE NEURONS IN CE
PROXIMAL AXON DOESN'T UNDERGO
DEGENERATION.
HERE THE ARROWHEAD IS SHOWING
YOU THE CELL BODY OF A NEURON
WHOSE AXON WAS CUT, AND THIS
CELL BODY HERE HAS AN AXON THAT
WAS UNCUT.
SO THIS IS WHAT HAPPENS.
NOW I'M GOING TO PLAY THE VIDEO
AND THIS IS REALLY SPED UP OVER
A LONG PERIOD OF TIME, 15 HOURS,
IN A FEW SECONDS, BUT YOU CAN
SEE THAT THAT CELL ENDS UP
DYING.
WE'RE VERY EXCITED ABOUT THIS
BECAUSE WE NOW HAVE A HUMAN
NEURON MODEL THAT UNDERGOES AXON
DEGENERATION AND CELL DEATH, AND
I DON'T HAVE TIME TO SHOW YOU
THIS WORK WHICH IS STILL
UNPUBLISHED, BUT JORGE HAS
DISCOVERED A NOVEL SIGNALING
CASCADE DOWNSTREAM OF DLK THAT
MEDIATES THIS.
AND SO I JUST WANT TO FINISH
WITH A BRIEF SUMMARY THAT I'VE
SHOWN YOU THAT THERE IS A LINK
BETWEEN THE AXON DAMAGE RESPONSE
AND NEUROINFLAMMATION.
WE THINK THIS COULD BE
PARTICULARLY RELEVANT IN THE
CONTEXT OF NEURODEGENERATIVE
DISEASE IN WHICH WE KNOW THAT
NEUROINFLAMMATION CAN PLAY
IMPORTANT ROLES, AND SO AXON
INJURY SIGNALING NOT ONLY
IMPACTS THE NEURON ITSELF, BUT
ALSO THE SURROUNDING TISSUE.
I'VE ALSO SHOWN YOU HOW WE CAN
USE SINGLE CELL TRANSCRIPTOMICS
TO DEFINE CELL TYPES SUCH AS
SPINAL MOTOR NEURONS, AND HOW WE
PLAN TO USE THIS TECHNOLOGY TO
INVESTIGATE HOW NEURON TYPES
MIGHT DIFFERENTIALLY RESPOND TO
INJURY.
AND WE HAVE ALSO COMPLEMENTED
WORK IN THE MOUSE MODELS WITH
STUDIES IN HUMAN NEURONS WHICH
CAN HELP ACCELERATE TRANSLATION
OF BASIC RESEARCH TO
CLINIC-USEFUL KNOWLEDGE.
AND I REALLY THINK THAT
FUNDAMENTAL KNOWLEDGE OF THE
KIND OF BASIC RESEARCH THAT WE
DO IS ESSENTIAL TO UNDERSTAND
NEURODEVELOPMENTAL AND
NEURODEGENERATIVE DISORDERS AND
ALSO TO DEVELOP CLINICAL
THERAPIES IN NEUROPROTECTION AND
NERVE REPAIR.
SO WITH THAT, I WOULD LIKE TO
JUST ACKNOWLEDGE THE MEMBERS OF
MY LAB WHO CONTRIBUTED TO THE
WORK THAT I SHARED TODAY.
I'VE UNDERLINED THEIR NAMES, AND
ALSO THANK ME MIE COLLABORATO ME
AT THE NIH INTRAMURAL PROGRAM.
THANK YOU VERY MUCH FOR YOUR
ATTENTION.
>>THANK YOU, DR. LE PICHON AND
DR. NARENDRA FOR SHARING YOUR
FASCINATING BODY OF WORK IN
OFFERING DEEPER INSIGHTS IN THE
UNDERSTANDING OF CELLULAR
MECHANISMS AND MODELS FOR NEURAL
DEGENERATION.
WE HAVE TIME FOR A FEW
QUESTIONS.
THE FIRST QUESTION IS ACTUALLY
FOR DR. NARENDRA.
SO, FANTASTIC LECTURE.
DO WE HAVE A MECHANISM FOR CHRIS
CRISTAE BECOMING -- OUTSIDE OF
MITOCHONDRIAL MEMBRANE?
IS THERE A MEMBRANE DISORDER OR
MEMBRANE MITOCHONDRIAL
DISRUPTION IN ALS OR
PARKINSON'S-TYPE DISEASE?
>>SO SORRY, I MISSED THE FIRST
PART OF THAT QUESTION.
>>DO WE HAVE A MECHANISM FOR
THE MITOCHONDRIAL CRISTAE
BECOMING FUSEOGENIC FROM THE
MITOCHONDRIAL MEMBRANE, AND THE
SECRETARY PART IS THERE SOME
SORT SORT OF MEMBRANE
MITOCHONDRIAL DISRUPTION IN ALS.
>>SO I THINK TO TAKE THE SECOND
PART OF THE QUESTION FIRST IN
PARKINSON'S DISEASE AND ALS, I
THINK THERE ARE OFTEN STRUCTURAL
CHANGES THAT ARE SEEN TO THE MY
TOE DONEMITOCHONDRIA THAT I SHOU
BEFORE.
I'M NOT SURE I ENTIRELY
UNDERSTAND THE FIRST QUESTION.
THERE'S AN OUTER MEMBRANE OF THE
MITOCHONDRIA AND INNER MEMBRANE
AND FUSION OF THE OUTER MEMBRANE
IS MEDIATED BY THESE -- IT'S
PROBABLY THE INNER MEMBRANE HAS
CRISTAE COMPONENT AND ALSO THIS
BOUNDARY COMPONENT, AND I THINK
OPA1 IS KIND OF ON THAT BOUNDARY
CLOSE TO THE CRISTAE JUNCTION,
SO PROBABLY THE FUSION DOESN'T
HAPPEN WHERE THE CRISTAE IS, PER
SE, BUT PROBABLY HAPPENS SORT OF
ADJACENT TO THE CRISTAE.
>>OKAY, THANK YOU.
FOR DR. LE PICHON, WHEN THE DLK
STRESS PATHWAY IS TURNED ON IN
NEURONS OF THE BRAIN, DOES IT
MEAN THAT THOSE CELLS ARE COMMIT
TODAY DIE?
>>SO WE THINK BASED ON OUR --
WELL, SO I THINK SOME MORE
RESEARCH IS NEEDED, BUT BASED ON
WHAT WE HAVE SEEN SO FAR WITH
THE PERIPHERAL -- THE PERIPHERY
PROJECTING NEURONS AND THEN
THIS -- SO THE DRG NEWER YONS
AND MOTOR NEURONS, WHEN WE DO
THOSE KINDS OF INJURIES IN THE
MOUSE, THOSE CELLS DO NOT DIE
AFTER AXON DAMAGE.
HOWEVER, WE'RE REALLY CURIOUS
ABOUT WHAT HAPPENS IN BRAIN
CELLS BASED ON OUR EXPERIMENTS
OF THE HUMAN NEURONS IN VITRO.
SO I WOULD PREDICT YES, ONLY
BECAUSE OF THE REDUCED CAPACITY
OF CENTRAL NERVOUS SYSTEM
NEURONS TO REGENERATE, BUT I
DON'T REALLY KNOW.
AND I THINK LOOKING AT HOW -- AT
THE IPT PLAY BETWEEN ABILITY TO
REPAIR AND A SURVIVAL IS ALSO AN
INTERESTING QUESTION.
>>THANK YOU.
FOR DR. NARENDRA, ANOTHER
QUESTION.
YOU'D MENTIONED ABOUT THE
DIVERSE PHENOTYPES IN
INDIVIDUALS WITH CHCHD10
MUTATIONS.
WHAT ACCOUNTS FOR THE DIVERSITY
OF THOSE PHENOTYPES?
>>WE DON'T FULLY UNDERSTAND IT,
BUT MY SUSPICION IS THAT THESE
MUTATIONS ARE CAUSING THE
PROTEINS TO MISFOLD IN DIFFERENT
WAYS, AND JUST LIKE IN DIFFERENT
FORMS OF TAUOPATHY, YOU CAN GET
ONE NEUROLOGICAL DISEASE VERSUS
ANOTHER DEPENDING ON WE NOW KNOW
DIFFERENT STRAINS -- DIFFERENT
WAYS IN WICHITA IS MISFORMED.
SAME THING SEEMS TO BE TRUE
ABOUT ALPHA SYNUCLEIN THAT
MISFOLDS IN PARKINSON DISEASE
AND ANOTHER DISEASE CALLED
MULTIPLE SYSTEM ATROPHY.
I THINK PERHAPS IN THE SAME WAY
THESE ARE CAUSING C10 TO MISFOLD
IN DIFFERENT WAYS, AND IF IT
MISFOLDS ONE WAY, IT'S MORE
TOXIC TO NEURONS AND IF IT
MISFOLDS ANOTHER WAY, IT'S MORE
TOXIC TO MUSCLE CELLS.
>>OKAY.
THANK YOU.
FOR --
>>SO FOR DR. LE PICHON, A
QUESTION.
HOW DOES KNOWING THE
TRANSCRIPTIONAL ABILITY OF
PARTICULAR NEURONS HELP ADVANCE
UNDERSTANDING OF
NEURODEGENERATIVE DISEASES?
>>SO ONE THING THAT'S REALLY
INTERESTING ABOUT DIFFERENT
NEURODEGENERATIVE DISEASES IS,
YOU KNOW, EACH ONE WILL HAVE A
PARTICULAR CONSTELLATION OF
SYMPTOMS, AND THAT'S PROBABLY
BECAUSE DIFFERENT NEURON TYPES
TEND TO BE MORE VULNERABLE THAN
OTHERS TO THE DIFFERENT -- IN
THE DIFFERENT DISEASE CONTEXTS.
SO I THINK THAT UNDERSTANDING
THE IDENTITY OF THE DIFFERENT
NEURON TYPES AT THE GET-GO CAN
KIND OF LAY THE GROUNDWORK FOR
THEN UNDERSTANDING HOW ONE TYPE
MIGHT BE MORE VULNERABLE TO A
CERTAIN TYPE OF STRESS THAN
ANOTHER, FOR EXAMPLE.
I THINK THOSE ARE REALLY CLEAR
EXAMPLE OF THAT IN PARKINSON'S E
SUBSTANTIA NIGRA NEURONS, FOR
EXAMPLE.
AND I THINK, YOU KNOW, THE FIELD
IS KIND OF MOVING IN THIS
DIRECTION TO START EXAMINING
THAT TYPE OF QUESTION.
>>THANK YOU.
SO FOR DR. NARENDRA, HOW -- IS
THE OME1/DELE -- FOR
MITOCHONDRIAL DYSFUNCTION?
>>I THINK IT'S STILL NOT
ENTIRELY CLEAR BUT IT SEEM LIKE
IT IS PROBABLY GOING TO BE
PRETTY BROAD.
SO AT THE END THERE, I MENTIONED
SORT OF THREE PAPERS THAT HAVE
BEEN PUBLISHED THIS YEAR,
INCLUDING OUR PAPER, SO WE HAVE
KIND OF AN EXAMPLE OF A
MISFOLDED PROTEIN STRESS THAT
SEEMS TO ACTIVATE THIS PATHWAY.
USING THE -- MODEL, WE SHOWED
THAT IF YOU JUST CAUSE AN --
DEFECT, YOU ACTIVATE THE SAME
PATHWAY.
ANOTHER TWO MODELLS SHOWING IF
YOU DISRUPT LIPID METABOLISM IN
THE MITOCHONDRIA TO INTERFERE
WITH KIND OF THE MEMBRANE, YOU
GET THE SAME PATHWAY ACTIVATED.
SO I THINK IT MAY TURN OUT
THAT -- PREDOMINANT WAY IN WITS
MITOCHONDRIAL STRESS SIGNALS
TO -- RESPONSE IN VIVO.
>>WELL, THAT ACTUALLY BRINGS US
UP TO THE HOUR.
AGAIN, I WANT TO THANK BOTH OF
YOU FOR YOUR EXCELLENT TALKS OF
YOUR INVESTIGATIONS TO OUR NIH
COMMUNITY.
I WISH ALL OF YOU A WONDERFUL
AFTERNOON.
THANK YOU.