Immunology in the skin

00:07:30
https://www.youtube.com/watch?v=_VhcZTGv0CU

概要

TLDRThe video explains the skin's role as a protective barrier and its complex immune functions. It describes the skin's structure, comprising the epidermis, dermis, and subcutaneous fat, while detailing the interactions of various immune cells, such as dendritic cells and T cells, in responding to pathogens and maintaining tissue homeostasis. The video also covers the mechanisms leading to skin disorders like psoriasis, emphasizing how immune responses can sometimes become dysregulated, causing chronic inflammatory conditions.

収穫

  • 🛡️ The skin serves as the body's primary barrier against pathogens.
  • 🔬 Immune cells in the skin maintain tissue homeostasis and activate immune responses.
  • 🧬 The skin is composed of the epidermis, dermis, and subcutaneous fatty tissue.
  • 🦠 Commensal microbes protect the skin and promote wound healing.
  • 🎯 Langerhans cells sample antigens and modulate immune responses.
  • 💡 Dendritic cells activate T cells and migrate to lymph nodes after pathogen encounter.
  • ⚔️ T cells play key roles in skin immunity, with memory T cells residing in the epidermis.
  • 📈 Psoriasis is a chronic inflammatory skin disease linked to immune response dysregulation.
  • 🧪 Genetic factors can increase susceptibility to skin disorders like psoriasis.
  • 🧘‍♂️ Autoimmunity can lead to skin conditions, highlighting the balance needed in immune responses.

タイムライン

  • 00:00:00 - 00:07:30

    The skin serves as the body's primary defense against environmental threats and pathogens, consisting of three main layers: the epidermis, dermis, and subcutaneous tissue. It hosts various microorganisms that aid in protection and healing. Epidermal cells, or keratinocytes, are vital for barrier function, continually replenished by basal keratinocytes. The dermis contains fibroblasts that produce collagen and elastin, contributing to skin structure. Additionally, immune cells interact closely with skin cells to maintain health, responding to pathogens through a specialized network involving various immune cell types. Dendritic cells play a crucial role in antigen capture and presentation, while T cells act as immune effectors, maintaining memory to swiftly respond to infections. However, dysregulation of immune responses can lead to skin disorders, exemplified by psoriasis, which is characterized by scaly plaques due to a complex interplay of genetic and environmental triggers, showcasing both protective and pathological roles of immune cells in the skin.

マインドマップ

ビデオQ&A

  • What are the components of the skin?

    The skin consists of the epidermis, dermis, and subcutaneous fatty region.

  • What role do commensal bacteria play on the skin?

    Commensal bacteria, fungi, and viruses help protect against pathogens and aid in wound healing.

  • What are Langerhans cells?

    Langerhans cells are specialized dendritic cells in the epidermis that sample antigens and can be either anti-inflammatory or activatory.

  • What triggers the immune response in the skin?

    The immune response in the skin can be triggered by pathogen encounter, tissue damage, or reactivation of viruses.

  • What is psoriasis?

    Psoriasis is a chronic inflammatory skin disease characterized by scaly, reddish plaques.

  • How can genetic factors influence psoriasis?

    Genetic studies have identified susceptibility genes linked to TH17 cells that may contribute to psoriasis pathogenesis.

  • What is the function of T cells in the skin?

    T cells act as immune effectors, with memory T cells rapidly reactivating upon encountering antigens.

  • What are the signs of an acute psoriatic lesion?

    Acute lesions are indicated by an accumulation of T cells and dendritic cells around blood vessels.

  • How do skin cells respond to inflammation?

    Skin cells, such as keratinocytes, can produce inflammatory mediators that recruit immune cells to the site of injury.

  • What is the impact of autoimmunity on the skin?

    Autoimmunity can lead to disorders like psoriasis, where the immune system mistakenly attacks skin cells.

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  • 00:00:01
    [Music]
  • 00:00:28
    e
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    the skin is the body's primary barrier
  • 00:00:34
    against physical insults and microbial
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    pathogens it represents a unique
  • 00:00:39
    environment in which immune cells
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    interact with skin cells to maintain
  • 00:00:43
    tissue homeostasis and induce immune
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    responses the skin is composed of
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    epidermis dermis and a subcutaneous
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    fatty region commensal bacteria fungi
  • 00:00:56
    and viruses living on the skin have
  • 00:00:58
    beneficial effects in the protection
  • 00:01:00
    against pathogens and in wound
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    healing the epidermis is composed of
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    Highly specialized epithelial cells
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    known as kattin aites they are
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    continuously replenished from just one
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    layer of Basil kattin aites which divide
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    frequently dead cells called corneocytes
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    form the outermost layer and are largely
  • 00:01:21
    responsible for the barrier function of
  • 00:01:23
    the
  • 00:01:24
    skin in the dermis cells known as fiber
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    blasts secrete elastin and coll fibers
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    that form a dense extracellular
  • 00:01:33
    Matrix blood capillaries irrigate the
  • 00:01:35
    dermis while lymph fluid is drained
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    through lymphatic vessels to lymph nodes
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    specialized immune structures in which
  • 00:01:41
    immune cells are activated after
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    pathogen
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    encounter diverse and functionally
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    specialized immune cells populate the
  • 00:01:51
    skin in the epidermis A specialized
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    subset of dendritic cells called lahan
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    cells sample antigen they project dend
  • 00:02:00
    upward towards the cornified epithelial
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    layer and Sample bacterial antigen such
  • 00:02:05
    as toxins lahan cells appear to be both
  • 00:02:08
    anti-inflammatory and activatory
  • 00:02:10
    depending on
  • 00:02:13
    context dendritic cells in the dermis
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    are highly efficient at capturing dead
  • 00:02:17
    cells and presenting antigen such as
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    viruses other intracellular pathogens or
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    skin Associated self antigen to te-
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    cells if dendritic cells are the immune
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    Sentinels t cells are the immune
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    effectors healthy skin contains more
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    than twice the number of tea cells found
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    in the blood most of them are memory tea
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    cells that have previously encountered
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    antigen and can be rapidly reactivated
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    tea cells in the epidermis are mostly
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    cd8 te- cells a subset that becomes
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    cytotoxic and kill target cells upon
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    activation they're long-term residents
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    in the epidermis mostly disconnected
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    from the
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    circulation tea cells in the dermis are
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    mostly helper CD4 te- cells which have a
  • 00:03:03
    more modulatory role in the immune
  • 00:03:05
    response a variety of other immune cells
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    such as natural killer cells eosinophils
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    and mast cells are present in the dermis
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    and might be involved in allergic
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    reactions in the
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    skin dendritic cells and catinos sites
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    sense tissue damage such as wounds or
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    cold sore lesions that occur when latent
  • 00:03:25
    herpes virus reactivates and they do
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    that through evolutionarily conserved
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    receptors that recognize pathogen
  • 00:03:32
    derived molecular patterns or host
  • 00:03:34
    derived molecules that are exposed by
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    cell death such as
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    DNA kattin Ayes produce antimicrobial
  • 00:03:41
    peptides which can kill bacteria
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    directly inflammatory mediators such as
  • 00:03:46
    interlukin 1 or il1 which activate
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    dendritic cells and chemokines which
  • 00:03:52
    recruit neutrophils macrophages and tea
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    cells activated dendritic cells migrate
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    to the lymph nodes where they present
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    antigen from the site of infection to
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    naive tea cells priming them to activate
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    and differentiate into infecta tea
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    cells activated tea cells return to the
  • 00:04:11
    skin and kill infected cartinos sites to
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    control viral infection or secrete
  • 00:04:16
    signals that recruit additional immune
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    affector
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    cells following viral clearance memory
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    CDH cells persist in the epidermis to
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    provide immunity for future encounters
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    with the same virus
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    immune responses can become disregulated
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    and cause skin disorders such as
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    psoriasis or atopic
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    dermatitis psoriasis is a lifelong
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    inflammatory skin disease characterized
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    by scaly reddish plaques a combination
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    of environmental and genetic factors
  • 00:04:47
    confer susceptibility to the
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    disease physical injury or inflammation
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    can trigger the formation of an acute
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    lesion the antigenic trigger is unknown
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    but current models proposed that
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    stressed carattino sites might release
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    self DNA which in complex with an
  • 00:05:04
    antimicrobial peptide activates dermal
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    plasmacytoid dendritic cells to secrete
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    high amounts of the antiviral mediator
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    into feon together with pro-inflammatory
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    il1 Alpha released by stressed kattin
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    Ayes interferon activates dermal
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    dendritic cells to promote te- cell
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    differentiation the earliest
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    recognizable change in the affected skin
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    is the accumulation of tea cells and
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    dendritic cells around blood vessels in
  • 00:05:31
    the
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    dermis an overt lesion occurs when cd8 T
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    cells dendritic cells and neutrophils
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    infiltrate the
  • 00:05:42
    epidermis specialized subsets of tea
  • 00:05:45
    cells secrete soluble mediators like
  • 00:05:47
    interferon gamma and il17 which
  • 00:05:50
    stimulate the proliferation of coratin
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    aites and this produces a marked
  • 00:05:53
    thickening of the
  • 00:05:56
    epidermis signals from the proliferating
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    coratin aites act as chemoattractants
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    for infiltrating
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    nutrifil cross talk between immune cells
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    cartin aites and dermal cells thus
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    contributes to tissue Remodeling and
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    amplification of this disregulated
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    immune
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    response without treatment acute
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    psoriatic lesions become chronic lesions
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    genetic Studies have identified
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    psoriasis Associated susceptibility
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    genes some of them linking th17 cells
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    the subset of te- cells that produce
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    il17 to psoriasis pathogenesis thus
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    immune cells in the skin exert important
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    roles in maintaining the barrier
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    function against pathogens but can also
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    become activated by self antigen or
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    harmless antigen to cause autoimmunity
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    or
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    [Music]
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    allergies
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    [Music]
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    [Music]
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    and
タグ
  • skin
  • immune system
  • epidermis
  • dermis
  • T cells
  • Langerhans cells
  • psoriasis
  • inflammation
  • autoimmunity
  • keratinocytes