sebaceous gland

Acne vulgaris: Origins, symptoms and current treatments

Acne vulgaris is a chronic inflammatory disease of the skin which affects most adolescents and is the cause of over half of all dermatology consultations. This pathology, which is characterized by a hypersecretion of sebum, can be the cause of physical complications and may also lead to psychological distress.

Physiology and functions of the sebaceous gland

The sebaceous gland is an organ located in the dermis. Its role is to synthesise and secrete sebum which is a component of the hydrolipidic film. The purpose of sebum is to protect the skin from external aggression and dehydration. Sebum also maintains the suppleness of the skin and hair.

Interleukin-17A-induced production of acute serum amyloid A by keratinocytes contributes to psoriasis pathogenesis

Acute-serum Amyloid A (A-SAA), one of the major acute-phase proteins, is mainly produced in the liver but extra-hepatic synthesis involving the skin has been reported. Its expression is regulated by the transcription factors NF-κB, C/EBPβ, STAT3 activated by proinflammatory cytokines.
granulation wound healing

Wound healing, granulation phase and maturation phase

The third phase of wound healing, consisting in the replacement of the provisional  fibrin matrix with granulation tissue once the wound has been debrided, includes several sub-phases: re-epithelialization, fibroplasia, collagen deposition and angiogenesis.

Wound healing, hemostasis phase and inflammatory phase

The inflammatory phase is characterized by the sequential infiltration of polymorphonuclear neutrophils (PMNs), monocytes/macrophages and lymphocytes. IL-8 facilitates PMNs migration from surrounding blood vessels.

Wound healing, overview

Wound healing is a complex and dynamic process of restoring skin cellular structures and tissue layers that involves multiple components: differentiated cells , stem cells , hair follicles, extracellular matrix (ECM) proteins, cytokines networks, microRNAs , blood vessels, nerves and mechanical forces.

Imiquimod-induced skin inflammation in mice is dependent on IL-1R1 and MyD88 signaling but independent of the NLRP3 inflammasome

The pathogenesis of inflammatory skin diseases such as psoriasis involves the release of numerous proinflammatory cytokines, including members of the IL-1 family. Here we report overexpression of IL-1α, IL-1β, and IL-1 receptor antagonist mRNA, associated to expression of IL-23p19, IL-17A, and IL-22 in skin cells

Androgens induce sebaceous differentiation in sebocyte cells expressing a stable functional androgen receptor

In order to study the impact of active androgens in sebocytes, we constructed a stable human sebocyte cell line derived from SEBO662 [17] constitutively expressing a fully functional AR. In these SEBO662 AR+ cells, dihydrotestosterone (DHT) induced AR nuclear translocation and the strong modulation of a set of transcripts (RASD1, GREB1...) known to be androgen-sensitive in other androgenic cells and tissues.

Study of proliferation and 3D epidermal reconstruction from foreskin, auricular and trunk keratinocytes in children

Our studies highlight the potential of foreskin tissue for autograft applications in boys. A suitable alternative donor site for autologous cell transplantation in female paediatric burn patients remains an open question in our department. We tested the hypothesis that in vitro studies and RHE reconstructive capacities of cells from different body sites can be helpful to select an optimal site for keratinocyte isolation before considering graft protocols for girls.

Epidermal healing in burns: autologous keratinocyte transplantation as a standard procedure: update and perspective

In the contexte of skin graft, cell suspensions transplanted directly to the wound is an attractive process, removing the need for attachment to a membrane before transfer and avoiding one potential source of inefficiency. Choosing an optimal donor site containing cells with high proliferative capacity is essential for graft success in burns.

Inhibition of keratinocyte differentiation by the synergistic effect of IL-17A, IL-22, IL-1α, TNFα and oncostatin M

This study highlights the precise role of cytokines in the skin inflammatory response (psoriasis). IL-22 and OSM more specifically drive epidermal hyperplasia and differentiation loss while IL-1α, IL-17A and TNFα were more involved in the activation of innate immunity.

Contribution of IL22 to experimental skin inflammation

Focused on in vitro human models, we present the mechanisms of action of IL22 as well as its involvement in structure, metabolism, differentiation, chemotaxis, antibacterial activity, innate immunity, and tissue remodeling of epidermis.

Atopic dermatitis: physio-pathology and clinical signs

Atopic dermatitis is the most common dermatosis affecting children: 65% of the patients are less than a year old and 85% are below 5 years. The prevalence of this pathology is constantly on the rise and currently affects 10 to 25% of the population.

Foreskin-isolated keratinocytes provide successful extemporaneous autologous paediatric skin grafts

We report a successful method for grafting paediatric males presenting large severe burns through direct spreading of autologous foreskin keratinocytes. This alternative method is easy to implement, improves the quality of skin and minimizes associated donor site morbidity. in vitro studies have highlighted the potential of foreskin tissue for graft applications and could help in tissue selection with the prospect of grafting burns for girls.

Keratinocytes under fire of proinflammatory cytokines: Bonafide innate immune cells involved in the physiopathology of chronic atopic dermatitis and psoriasis

Specific cytokine environment deregulation plays a central role on skin morphology and innate immunity, moving towards specific pathologies and opening the way to new therapeutic strategies.

Atopic dermatitis - initiation and chemokines activation step

The skin lesions facilitate the passage of an antigen that the subject has previously been sensitized to.
atopic dermatitis

Atopic dermatitis - immune response and skin lesions

TH2/TH22 immune response and other agents of atopic dermatitis After polarization, the Th2 and Th22 TL migrate to the lesion area, where they release type Th2 (IL-4, IL-5, IL-13, IL-31, TNF-α) and Th22 (IL-22) cytokines respectively. These Th2/Th22 cytokines have different functions in the immunity response.

Immortalized sebocytes SEBO662 can spontaneously differentiate into a sebaceous-like phenotype when cultured as a 3D epithelium

SEBO662 multilayers spontaneously differentiate into a sebaceous-like structure as shown by the strong polarized expression of the late sebaceous marker EMA, the overexpression of some lipogenic markers and lipid production on the upper side of the epithelium.

Quantitative and qualitative study in keratinocytes from foreskin in children: Perspective application in paediatric burns

Keratinocytes from foreskin have a high capacity for division. A potential source of cells to provide coverage in paediatric burns.

Skin inflammation induced by the synergistic action of IL17A, IL22, OSM, IL1α and TNFα recapitulates some features of psoriasis

Our results demonstrate the important potentiating activities of IL17A, IL22, oncostatin M, TNF-alpha, and IL1alpha on keratinocytes. This is particularly interesting in the context of psoriasis where these cytokines are overexpressed and could synergize to play an important role in upregulation of chemokines and antimicrobial peptides production.