RESUMO
The coordinated migration and maturation of dendritic cells (DCs) such as intraepithelial Langerhans cells (LCs) is considered critical for T cell priming in response to inflammation in the periphery. However, little is known about the role of inflammatory mediators for LC maturation and recruitment to lymph nodes in vivo. Here we show in human dermatopathic lymphadenitis (DL), which features an expanded population of LCs in one draining lymph node associated with inflammatory lesions in its tributary skin area, that the Langerin/CD207(+) LCs constitute a predominant population of immature DCs, which express CD1a, and CD68, but not CD83, CD86, and DC-lysosomal-associated membrane protein (LAMP)/CD208. Using LC-type cells generated in vitro in the presence of transforming growth factor (TGF)-beta1, we further found that tumor necrosis factor (TNF)-alpha, as a prototype proinflammatory factor, and a variety of inflammatory stimuli and bacterial products, increase Langerin expression and Langerin dependent Birbeck granules formation in cell which nevertheless lack costimulatory molecules, DC-LAMP/CD208 and potent T cell stimulatory activity but express CCR7 and respond to the lymph node homing chemokines CCL19 and CCL21. This indicates that LC migration and maturation can be independently regulated events. We suggest that during DL, inflammatory stimuli in the skin increase the migration of LCs to the lymph node but without associated maturation. Immature LCs might regulate immune responses during chronic inflammation.
Assuntos
Células de Langerhans/imunologia , Lectinas Tipo C , Linfonodos/imunologia , Linfadenite/imunologia , Lectinas de Ligação a Manose , Pele/imunologia , Adolescente , Adulto , Antígenos CD , Antígenos de Superfície/biossíntese , Biomarcadores , Diferenciação Celular , Movimento Celular/imunologia , Células Cultivadas , Quimiocina CCL19 , Quimiocina CCL21 , Quimiocinas CC/imunologia , Quimiocinas CC/farmacologia , Doença Crônica , Escherichia coli/imunologia , Feminino , Antígenos HLA-DR/biossíntese , Humanos , Imunofenotipagem , Células de Langerhans/citologia , Células de Langerhans/fisiologia , Ligantes , Lipopolissacarídeos/imunologia , Lipopolissacarídeos/farmacologia , Linfonodos/citologia , Linfonodos/patologia , Linfadenite/patologia , Masculino , Pessoa de Meia-Idade , Monócitos/citologia , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Mycobacterium bovis/imunologia , Receptores CCR7 , Receptores de Quimiocinas/imunologia , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
SYNOPSIS: Much effort has been placed in cosmetic research for better understanding of the effects of ageing on skin's appearance, structure, mechanical properties and function. It is now of common knowledge that UV radiations induce pre-mature skin ageing notably in the epidermis where UV radiations induce keratinocyte differentiation. As UV radiations have also been shown to regulate the pro-opiomelanocortin (POMC) peptide family in the skin and because no study has been conducted so far to investigate the age-related changes in POMC and related receptors, we analysed POMC, MC-1R, MC-2R and MOR-1 at mRNA level and MC-1R, MC-2R and MOR-1 at protein level too in primary cultures of normal human keratinocytes obtained from female donors aged from 17 to 75 years old. Regarding the gene expressions, we observed that MC-1R, MC-2R and MOR-1 suffered a dramatic decrease after 50 years of age, whereas POMC increased five-fold. Western blot analysis confirmed these results except for MOR-1 whose expression appeared to decrease at older age, around 70 years old. Immunostainings specific to MC-1R, MC-2R and MOR-1 performed on full-thickness skin biopsies also revealed an intense staining in the basal and spinous layers of a 30-year-old donor, whereas no reactivity could be observed in a 60-year-old one. We conclude that POMC and POMC-related receptors suffer a dramatically disturbed balance with ageing and that this may be implicated in the general process of skin ageing.
Assuntos
Envelhecimento/fisiologia , Epiderme/fisiologia , Queratinócitos/fisiologia , Pró-Opiomelanocortina/fisiologia , Receptor Tipo 1 de Melanocortina/fisiologia , Receptor Tipo 2 de Melanocortina/fisiologia , Adolescente , Hormônio Adrenocorticotrópico/genética , Hormônio Adrenocorticotrópico/fisiologia , Adulto , Idoso , Biópsia , Células Epidérmicas , Epiderme/química , Feminino , Humanos , Queratinócitos/química , Queratinócitos/citologia , Pessoa de Meia-Idade , Pró-Opiomelanocortina/genética , RNA/química , RNA/genética , Receptor Tipo 1 de Melanocortina/genética , Receptor Tipo 2 de Melanocortina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Adulto Jovem , alfa-MSH/genética , alfa-MSH/fisiologia , beta-Endorfina/genética , beta-Endorfina/fisiologiaRESUMO
We have used indirect immunogold electron microscopy to compare the respective density of cell membrane determinants revealed by OKT6 and OKT4 monoclonal antibodies on normal human Langerhans cells (LC): 12.9 +/- 3.5 gold granules were noted per cell section on OKT4-positive LC whereas 236.8 +/- 23.5 granules were counted per cell section on OKT6-reactive cells. These results confirm that human LC react with OKT4 antibody and they demonstrate a marked quantitative difference on LC surface between the antigenic determinants recognized by OKT6 and OKT4 antibodies.