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biol clocks > Exam 4 > Flashcards

Exam 4 Flashcards

immunology, cancer, aging, exercise, Mike young

1
Q

Anatomical and chemical barriers

A

continuous
-physical barrier-
ex. Mucus
saliva
stomach acid
tears
skin

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2
Q

Intrinsic

A

Immediate
-Intrinsic-
ex. Autophagy
Apoptosis
MicroRNAs
CRISPRs

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3
Q

Innate

A

Minutes/hours
-Innate-
(not specific to the pathogen)
ex. Natural killer cells
Complement
Antigen-presenting cells
Neutrophils
Cytokines

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4
Q

Natural killer cells

A

Activated by cytokines, recognize changes in cell surface, secrete perforins (poke holes in cell membranes) and granzymes (activate apoptosis). Kill tumor cells and infected cells

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5
Q

Complement system

A

series of serum proteins that help in later (antibody) responses
*helps the movement

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6
Q

Neutrophils

A

Initial response to pathogens, induce inflammation (but need to go away first)

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7
Q

Cytokines

A

Stream of info to the rest of the immune system abt what kind of pathogen they have been exposed to
(specific: interferons)

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8
Q

Acquired immunity

A

Hours/days
-adaptive-
-very specific to pathogen-
ex. T cells
B cells

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9
Q

T cells

A

(Cytotoxic B cells) destroy infected cells (important for intracellular pathogens)
intracellular

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10
Q

B cells

A

Induce and mature plasma cells to make antibodies and those will circulate and destroy pathogens
Bacterial, too big to get in

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11
Q

what’s the only immune defense thats available after an organism is exposed to a pathogen?

A

Innate immune response

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12
Q

Adaptive response takes…?

A

a week to produce antibodies

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13
Q

Innate/Adaptive system differences

A

Both derive from hematopoietic stem cells:
Origin:
Innate= Myeloid linage Characteristics: Non-specific, rapid.
❄︎Components: Physical barriers, cellular components (e.g., phagocytes), soluble factors.
❄︎Recognition: Pattern recognition receptors (PRRs) detect pathogen-associated molecular patterns (PAMPs).
❄︎Response: Triggers inflammation, phagocytosis, and activation of immune cells.
❄︎Memory: Lacks immunological memory; response does not improve upon repeated exposure

Adaptive= Lymphoid linage
❄︎Characteristics: Antigen-specific, slower.
❄︎Components: Lymphocytes (B cells, T cells), NK cells.
Recognition: Specific recognition of antigens presented by antigen-presenting cells.
❄︎Response: Tailored response including antibody production, cytotoxic T cell activation, and immune cell coordination.
❄︎Memory: Develops immunological memory for faster and stronger responses upon re-exposure.

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14
Q

Antigen

A

Substance that is capable of stimulating an immune response.
Foreign antigens and autoantigens

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15
Q

Interferons

A

type of cytokine that protects cells from damage and death, but they do not play a major role in pathogen clearance

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16
Q

Phagocytes (macrophages, dendridic cells)

A

Internalize dead cells, cell debris, pathogens, including viral proteins.
*Activated by cytokines
*can present antigens on the cell surface

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17
Q

Granulocytes (neutrophils, eosinophils, basophils, mast cells)

A

Neutrophils usually the first innate cells recruited to infection site, they have phagocytic activity

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18
Q

Innate immune system mechanism

A

Pathogen- (cut/mosquito)–>
pattern recognition receptors (will recognize patterns of pathogens that are different from ours) –>
cytokines will be produces and will activate
–>
our innate response–>

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19
Q

Interferons create an antiviral state by shutting down ____and ____. Not specific to pathogen, so the response need to be____

A

transcription; translation; short lived

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20
Q

Sentinel cells

A

They patrol all our tissues, looking for signs of change
*Dendritic cells, macrophages, NK cells

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21
Q

Tnf-⍺

A

early warning signal in the innate immune response, and causes inflammation

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22
Q

step by step inflammation

A

❁Pathogen will induce an innate immune response, which will lead to the production of cytokines.
❁Those cytokines will induce inflammation, antipathogen state thru interferons and signal to sentinel cells that something is wrong.
❁They will move to the site of pathogen and mature and engulf debris, including pieces of the pathogen and present those short peptides or antigens, on cell surface.
❁Through inflammation, they will be able to migrate through lymph nodes, where they will talk to cells to adaptive immune response (immature T and B cells) and will signal to them that there is a big problem (takes several days)

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23
Q

when cells are expressing antigens on MHC class I molecules, this is recognized by what type of cells

A

NK cells and T cells

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24
Q

When are NK cells ONLY active

A

when MHC class I is not present

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25
Q

Helper cell send signal of wether it should be cytotoxic or B cells:

A

*Intracellular: will lead to maturation cytotoxic T cells
*Extracellular: produces diff type of cytokine, will lead to maturation of B cells

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26
Q

Experiment with LPS and mice:

A

If you give mice (nocturnal) at the end of their rest period, you get a much greater cytokine response than if you give it at the end of day.
*This is attributed to circadian rhythms in PRRs and cytokine production

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27
Q

Rhythms in NK cells?

A

active at night in producing the proteins, NOT during the day (in nocturnal rodents)
*

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28
Q

What would happen if you knocked down PER2 in NK cells

A

Leads to a reduction of granzyme B and perforin proteins being produced, but are still rhythmic

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29
Q

What is the source of rhythms in immune cells?

A

In some cases there is control by both the local molec. clock ( can either prevent or reinforce signal) and the SCN pacemaker

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30
Q

A robust rhythm in NK cells in granzyme and perforin levels require both ____and the _____

A

NK clock; SCN clock

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31
Q

T and B cell numbers are generally___at night and ___during the day

A

high; low

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32
Q

Which data supported the rhythm of T cells in the blood is under control of the circadian rhythm in cortisol production?

A

Blocking the morning rise of cortisol in human subjects with a drug called metyrapone prevents the morning decrease of T cell # in the blood and inhibits upregulation of CXCR4 T cell receptor

decrease in T cell #s in the morning coincides w the rise in cortisol

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33
Q

Mutations in ___ and ____ increase the risk of MS

A

BMAL1 and CLOCK

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34
Q

Loss of ___in T cells, or ____knockout mice lead to increased severity of MS due to increased infiltration of T cells into the CNS.

*What treatment reduced the severity of the disease?

A

BMAL; REV-ERB

*agonist of REV-ERB

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35
Q

Why do most asthma attacks occur at night?

A

In part, because of bronchial airway constriction, but also bc there is also a circadian rhythm in inflammatory cells in asthmatic lung

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36
Q

Patients with cognitive disorders showed…?

A

A loss of circadian rhythms in microglia associated with increased inflammation

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37
Q

Cancer immunity cycle

A
  1. Cancel cell antigen presentation
  2. Activation of effector immunity cells
  3. Trafficking and infiltration of immune cells to tumors
  4. Elimination of cancer cells
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38
Q

What may affect the recognition and killing of cancer cells?

A

Clocks in T cells and NK cells (along with the activation of macrophages and DC’s)

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39
Q

Negatively correlated genes

A

involved in energy metabolism and inflammation

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40
Q

Positively correlated genes

A

Associated with DNA repair, microtubule organization and RNA transport

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41
Q

Circadian changes in aged mammals:

A

*Weaker entrainment
*Loss of SCN output
*Attenuated peripheral rhythms
*=Changes in behavior

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42
Q

Why is there weaker entrainment in aged mammals?

A

Catarats reduce light input in eyes, which affects melanopsin that regulates clock

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43
Q

What was found in the neuronal firing rate in young vs old hamastes?

A

Amplitude of rhythm of neuronal firing in the SCN goes down with aging due to loss of synchrony

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44
Q

What was found in drosophila mutation of clock genes?

A

Knockout of core clock genes affects lifespan of flies

45
Q

When they grafted fetal SCN tissue into old hamsters, what occurred?

A

Restoration of damped rhythms and increased longevity
-restored function and lifespan

46
Q

When looking at tissues of mice at different age stages, what did they conclude?

A

In older mice, they lose amplitude in rhythm, and there was an increase in gene expression variability

47
Q

When a study was done in adults, they concluded that as organisms age…?
What could extend lifespan?

A

*metabolic function tends to decline attributed to changes in energy metabolism, nutrient sensing, and metabolic signaling pathways (peripheral tissues)

*To extend lifespan, caloric restriction and time restricted feeding.

48
Q

What is the NAD consuming enzyme (has rhythms) in NAMPT? 〰

A

SIRT1

49
Q

The levels of the critical metabolite, NAD+, go down with____, and reduced NAD+ levels have been associated with____

A

age; decreased circadian amplitude in mice

50
Q

why do the levels of NAD change as we age?

A

Because there are NADases that can degrade NAD to keep NAD levels at homeostatic levels. So, as CD38 (NADase) goes up, NAD and mitochondrial function go down

51
Q

When looking at NAD+ /NR and aging, what did the study find?

A

looked at: BMAL1 recruitment, cellular oscillations, rhytmic respiration, activity rhythms

*when looking at PER2 (-) levels, they were much higher in old mice, but when treated with NR, it reduces the levels of PER2,
*along with restoring mitochondrial respiration
*and restores BMAL1 chromatin binding and function

52
Q

If we can restore NAD levels by adding one of the precursors in the salvage pathway (ie. NR), you can boost…?

A

the amplitude

53
Q

NAD dependent acetylase has an important role in regulating the clock because

A

It controls the modification by adding an Acetyl group to BMAL1 and PER2 in mammals

54
Q

SIRT1 deletions have a…

A

…premature aging phenotype: disrupted activity rhythms, increased pro-inflammatory markers

55
Q

SIRT1 overexpression leads to…?

A

an increased lifespan in mice

56
Q

Molecular connections btwn aging and the clock

A

❤︎When CLCK and BMAL1 are interacting and bound to promoters, BMAL gets acetylated.
❤︎When acetylated, it helps to recruit CRY1 and PER (repressors) to inactivate CLCK and BMAL
❤︎SRT1 comes in and can deacetylate PER2
❤︎ and when it becomes deacetylated, it leads to its degradation

57
Q

SIRT-1 inhibits PER2 by____,which promotes____

A

deacetylation; degradation

58
Q

In the absence of SIRT1, PER2 is…?

A

stable leading to a repressive state and low amplitude rhythms

59
Q

A prolonged repression in Old individuals will influence?

A

amplitude, phase, and period of the clock

60
Q

as we age, ribosomes…

A

make more mistakes in translation

61
Q

Circadian clock control of ____drives rhythms in translation and stop codon readthrough

A

ribosome composition

62
Q

Circadian rhythms in the levels of____affect rhythmic translation and translation fidelity

A

tRNA synthetases

63
Q

The reason translation fidelity goes down as we age is because?

A

The amplitude of the clock is also going down (period lengthens)

64
Q

What did they find mCherry?

A

During aging, there is a significant increase in Met into mCherry (flurorescence) Met72–>Glu72

65
Q

adding NMN (precursor to NAD synthesis) did what in Neurospora?

A

*increased amplitude
*doubles the lifespan
*helps maintain a precise clock

66
Q

If you ablate the SCN or put a mouse in a “jet-lag state”, what was found?

A

*promote tumor growth of tumor grafts and shows altered immune function (T-cell response)
*accelerates tumor growth in carcinogen-induced tumors and grafted melanomas
*promotes breast cance cell metastasis in mice

67
Q

Potential ways that the clock could influence cell growth and cell division

A

*cell cycle gating
*DNA damage repair
*Apoptosis
*Autophage
*Immune function
*Hypoxia
*Cellular redox
*mitochondrial function

68
Q

Disrupted circadian rhythms (cancer, obesity, aging)

A

*Uncontrolled proliferation
*Metastastic spread
*Escaping apoptosis
*Immune evasion
*Enhanced angiogenesis
*Anti-cancer drug resistance

69
Q

Inactivation of BMAL1or CLOCK:

Overexpression:

A

inactivation: increases tumor proliferation in several types of cancer, including colon and pancreatic cancer

overexpression: Supresses tumor cell proliferation

70
Q

What are some ways we can fix the clock in cancer?

A

1) Training clocks (exercise, light, food)
2) Drugging clocks (CRY 1/2, CKIs, Rev-erba/B)
3) Clocking medicine (dose-timing of anti-cancer drugs)

71
Q

Downregulation or upregulation of Per1, Per2, and Cry1 (negative elements)…? (cancer)

A

promotes or supresses tumor incidence proliferation, respectively

72
Q

MYC

A

*oncogene: when misregulated, it can promote cancer
* Transcription factor that activates genes involved in proliferation
*one of the only genes where a mutation on its own with no other effects can lead to cancer
*clock regulates it

73
Q

CRY2 binds to phosphorylated MYC to…

A

promote its ubiquitination and degradation

As a result, in the absence of CRY2, MYC is stabilized

74
Q

MYC then binds to the E-box of Rev-ERB (negative regulator of BMAL) which results in..?

A

down-regulation of BMAL1 and leads to overall clock disruption

75
Q

___silencing can induce cell cycle arrest and apoptosis in patient derived glioblastoma, whereas____overexpression promotes breast cancer cell invasion and metastases

A

BMAL1

76
Q

___can improve DNA repair in some tumors, and enhance p53 (a - regulator of the cell cycle) degradation in bladder cancers.

A

CRY1

77
Q

Circadian clock compoments may either accelerate tumor progression or inhibit tumorigenesis depending on….?

A

the tissue or cell type

78
Q

What is chronotherapy?

A

Timing of the drug delivery at the appropriate phase of the circadian rhythm to achieve optimal efficacy.

79
Q

What is the rationale for chronotherapy?

A
  1. Efficacy of an agent may vary with time of the day depending on its mechanism of action
  2. Pharmacokinetics and metabolism of agents may vary with circadian phase
  3. Toxicity of agents may vary with time of the day
80
Q

What are some ways to train the clock in regards to chronotherapy?

A
  1. Daytime blue light
  2. Bright light in the morning
  3. Time restricted feeding
  4. Chronic calorie restriction
  5. Chemo plus exercise (but did not include day specific exercise)
81
Q

When talking about chronotherapy and drugging the clock, what has been found about both CK1 and CK2 inhibitors?

A

CK1 inhibitors have antitumor effects in breast cancer, and some decrease cell proliferation and increase apoptosis in colon, liver, and other human cancer cells

CK2 inhibitor lengthens circadian period that inhibits growth of human and mouse cancer cells.

82
Q

Agonists of REV-ERB have selective anticancer properties in brain, leukemia, breast, colon, and melanoma cancer cell lines by…?

A

inhibiting autophagy and lipogenesis necessary for cancer cell survival and metastasis

83
Q

Inhibition of ROR inhibits____and helps induce____

A

prostate, pancreatic, breast cancer; T cells

84
Q

What are some things Nobiletin (agonist of ROR) do in regards to cancer cells?

A

*induce cell cycle arrest
*suppress migration and invasion
*upregulate tumor supressors
* increase chemotherapt sensitivity for many different cancer types

85
Q

CRY inhibitor KL001 shown to_____, but another study showed that KL001 promotes____

A

have antitumor activity in patient derived glioblastoma cells; cell migration in osteosarcoma

86
Q

A higer T-cell infiltration observed in metastatic melanoma that expresses high levels of____

A

BMAL1

87
Q

If patients undergo aortic valve replacement surgery in the morning, ….

A

it reduces myocardial injury and postoperative morbidity

88
Q

Which of the following best describes the most recent work of Dr. Michael Young?
a. Identification of mutations in humans that are associated with sleep disorders.
b. Identification of CLK as a component of the fly molecular clock.
c. Identification of genes involved in light entrainment of the clock.
d. Identification of kinases that phosphorylate human clock components

A

a. Identification of mutations in humans that are associated with sleep disorders.

89
Q

What initial major contribution did Dr. Michael Young make towards the discovery of Per
in Drosophila?
a. He generated genomic DNA libraries.
b. He developed a method to record fly activity rhythms.
c. He identified mutations that disrupted Per gene function.
d. He genetically mapped the Per gene to a specific region of the X chromosome

A

d. He genetically mapped the Per gene to a specific region of the X chromosome

90
Q

Since the mutation is found in multiple members of each family, what can be concluded?

A

all tissues should be affected

91
Q

In studies of several unrelated families, presence of____predicted DSPD. The penetrance and frequency of this allele suggests a broad contribution to DSPD world-wide.

A

Cry1Δ11

92
Q

Cry1Δ11 shows enhanced binding to ____and ____in mouse and human cultured cells, and Cry1Δ11 appears to be a _____

A

CLCK, BMAL1; transcriptional inhibitor

93
Q

Competitive binding to CLCK/BMAL1 suggests….?

A

A basis for inheritance as a dominant trait

94
Q

_____ expression is sufficient to legthen the period of mouse and human fibroblast rhythms

A

Cry1Δ11

95
Q

What is Shogo Sato’s main goal in the lab?

A

Developing chronobiological intervention approaches for human health promotion, specifically exercise

96
Q

At what time do we have greatest cardiovascular and skeletal muscle strength, along with highest body temperature and blood pressure?

A

5 pm

97
Q

When does melatonin secretion begin?

A

9 pm

98
Q

Circadian disruption leads to

A

physical and mental dysfunction
(24 hr access to food disrupts clock in metabolic organs)

99
Q

What was found when mouse ate in the rest phase?

A

Developed obesity

100
Q

What happens when we use time-restricted feeding method?

A

*Adiposity
*Glucose intolerance
*Leptin resistance
*Liver Pathology
*Inflammation
*Motor coordination

101
Q

When putting two mice in a treadmill, one running late in the evening, and one during early morning, what data was found?

A

When measuring the blood glucose and muscle glycogen, there was only reduced blood glucose levels in early active phase

102
Q

Increased amount of carnitin bound fatty acid indicated…?

A

higher activity of lipid utilization in SM

103
Q

Why do we have a higher performance during ZT3 (during fed) instead of ZT15 (during fasted)?

A

Because in ZT15 (morning), we are metabolically fed, so we have no stored energy to use

104
Q

If you want to reduce fat mass in adipose tissue, when would be the best time to exercise?

A

ZT15

105
Q

Sato’s study found specifically in blood glucose in young vs old?

A

Reduces blood glucose levels only in young in early morning exercise

106
Q

When is the best time to exercise to prevent tumors?

A

Morning exercise

107
Q

When is the best time to exercise to erase fear memory?

A

Late evening exercise

108
Q

What factors need to be considered in chronotherapy?

A

*Absorption
*Distribution
*Metabolism
*Excretion
*half-life of drugs
*Cycling of non-specific targets to reduce toxicity

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