9. TA lectures

Question 1

Atopic dermatitis can be caused by…

Answer 1

microbial dysbiosis, genetic mutations, skin barrier disruption, immune dysregulation, allergen exposure

Question 2

physical burden of atopic dermatitis

Answer 2

skin pain
sleep disturbance
depression and anxiety
asthma, allergies, hay fever
allergic contact dermatitis
infections
cardio-metabolic disorders

Question 3

skin microbial dysbiosis in atopic dermatitis

Answer 3

skin barrier disruption causes a decrease in commensals and AMP
results in an increase of IgE, eosinophils, and CCL17

Question 4

Mast cells in Atopic dermatitis

Answer 4

• IgE bound to mast cell can cause imflammation (immunological)
• pathogen detection and surveillance in barrier tissues
• have a spatial and temporal advantage over other leukocytes

Question 5

MRGPRX2/b2 mediated mast cell activation

Answer 5

• MRGPRX2 is expressed in human connective tissue mast cells
• are receptors of cationic ligands
• cause non-immunologic mast cell activation (IgE independent)

Question 6

how do mast cells and S.aureus interact in the occurrence of AD

Answer 6

• increases s.aureus = decreased microbial diversity
• s.aureus produces d-toxin which activates mast cells and induces AD-like inflammation

Question 7

what renders mast cells “sentinels” of the body

Answer 7

• tissue-resident cells found in host-environment junctions
• possess a broad repertoire of receptors to detect a variety of molecules
• activation occurs in seconds to minutes
• roles in allergy and infection

Question 8

MRGPRX2/b2 receptor expression and activation

Answer 8

• found in connective tissue mast cells
• activated by a variety of cationic (positive) compounds
• mediates susceptibility to bacterial infection

Question 9

what are examples of cations (bacterial molecules) that the MRGPRX2 receptor binds

Answer 9

• quorum-sensing molecules
• neuropeptides
• anti-microbial peptides

Question 10

what is catestatin

Answer 10

a neuroendocrine AMP which has antimicrobial and immunomodulatoy properties
its activation and improve the process of healing infected wounds

Question 11

catestatin induces…

Answer 11

MC histamine and PGD2 release through MRGPRX2

Question 12

effects of S.aureus toxins

Answer 12

activates T-cells
leukocyte lysis
host cell lysis
compromise physical barriers

Question 13

examples of toxins from s.aureus

Answer 13

TSST1
staphylococcal enterotoxins
leukocidins
a-hemolysin

Question 14

how does s.aureus evade the immune system

Answer 14

interferes with complement activation
fibrin sheild

Question 15

what does SCIN do

Answer 15

stabilizes inactive C3 convertase to prevent further action of the complement cascades

Question 16

fibrin shield of S.aureus to evade the immune system

Answer 16

ClfA proteins bind to host structural proteins to promote adhesion
shield MAMPs by coating the bacterium with host proteins to block detection of peptidoglycan

Question 17

how does S.aureus invade host cells and cause bacteremia

Answer 17

vascular wall adhesion
blood vessel damage
SpA-mediated B-cell death
activation of prothrombin
ClfA-Fibrin interactions