Module 1: Pathophysiology, Skin Barrier Damage, and Ceramide Depletion Welcome to your Module 1: Pathophysiology, Skin Barrier Damage, and Ceramide Depletion Name Institute Email Phone City IADVL / SES membership number Which ceramide subclass is covalently bound to involucrin on the cornified envelope to establish the cornified lipid envelope (CLE) scaffold? Cer[NP] Cer[EOS] Cer[AS] Cer[NS] None In the stratum granulosum, which tight junction protein is directly downregulated by IL-4 and IL-13, leading to enhanced antigen penetration? Claudin-1 Claudin-5 Desmoglein-1 Corneodesmosin None Which epidermal-specific ceramide synthase is suppressed by Th2 cytokines (IL-4/IL-13), impairing the synthesis of very long-chain ceramides (C24–C32)? CerS1 CerS2 CerS3 CerS6 None Which cytokine acts predominantly through the IL-31RA/OSMR complex on sensory neurons to serve as the primary mediator of pruritus in AD? IL-22 IL-31 IL-17A IL-10 None How does elevated stratum corneum pH secondary to filaggrin deficiency alter enzymatic barrier homeostasis? Inhibits kallikrein-5 and activates LEKTI Activates acid sphingomyelinase and beta-glucocerebrosidase Inhibits beta-glucocerebrosidase and promotes unrestrained KLK5/KLK7 activity Upregulates ABCA12 lipid loading None 1 out of 2 In lipidomic analysis of AD stratum corneum, which shift in ceramide chain length distribution is typically observed? Selective increase in C24–C26 ceramides with depletion of C16–C18 ceramides Selective reduction in long-chain ceramides (C24–C26) with a relative increase in short-chain ceramides (C16–C18) Uniform elevation of all ceramide chain lengths Complete loss of short-chain ceramides only None What distinguishes intrinsic AD from extrinsic AD immunologically and clinically? Intrinsic AD shows high total serum IgE with purely Th1-mediated inflammation Intrinsic AD presents with normal serum IgE levels and mixed Th2/Th1/Th17 cytokine activation Intrinsic AD accounts for 70–80% of all atopic dermatitis cases Intrinsic AD exhibits intact filaggrin expression and zero TEWL elevation None According to the "bricks and mortar" model of the stratum corneum, what proportion of total intercellular lipid mass is comprised of ceramides? Roughly 10% Roughly 25% Roughly 50% Roughly 85% None In the sphingomyelin hydrolysis pathway, which enzyme hydrolyzes lamellar body-derived sphingomyelin into ceramide in the stratum corneum extracellular space? Serine palmitoyltransferase (SPT) Acid sphingomyelinase (aSMase) Beta-glucocerebrosidase (GBA) Transglutaminase-1 None In pediatric AD patients with loss-of-function FLG mutations, barrier disruption is characterized by which immune polarization in the stratum corneum compared to adult AD? Th1-predominant environment Th17-enriched environment Pure Th22 environment without Th2 involvement Complete suppression of all adaptive immune axes None 2 out of 2 Previous Start Quiz Next Time's up Leave a Reply Cancel replyCommentEnter your name or username to comment Enter your email address to comment Enter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
