RESUMO
We previously reported that a pathogenic abnormality in the barrier and water-holding functions of the stratum corneum (SC) in the skin of patients with atopic dermatitis (AD) is mainly attributable to significantly decreased levels of total ceramides in the SC. That decrease is mediated by the abnormal expression of a novel ceramide-reducing enzyme, sphingomyelin/glucosylceramide deacylase (SGDase), which is the ß-subunit (ASAH1b) of acid ceramidase. In this study, we determined whether mice overexpressing ASAH1b in their epidermis develop AD-like skin symptoms. We generated transgenic (TG) mice overexpressing ASAH1b, regulated by the involucrin promoter, to localize its expression in the upper epidermis. After hair removal using a depilatory cream containing glycolic acid, the TG mice without any visible skin inflammation at 8 weeks of age had increased levels of ASAH1b and decreased levels of SC ceramide, with disrupted barrier functions measured by trans-epidermal water loss compared to the wild-type (WT) mice. Interestingly, enzymatic assays revealed that SGDase activity was not detectable in the skin of the TG mice compared to WT mice. Immunological staining revealed that there was an increased expression level of IL-33 in the epidermis and an accumulation of macrophages in the dermis of TG mice compared to WT mice, which are phenotypic characteristics of AD, that were exacerbated by tape-stripping of the skin. In the skin of the TG mice, the mRNA levels of IL-5, CCL11, IL-22, CXCL10, and IFNγ were significantly upregulated compared to the WT mice, and tape-stripping significantly increased the mRNA levels of IL-4, IL-33, CXCL1, CXCL12, TLR9, and CD163 compared to WT mice. These findings strongly indicate that the skin of the depilatory cream-treated TG mice exists in an atopic dry skin condition that is highly sensitive to various environmental stimuli. The sum of our results suggests that ASAH1b itself, even in the absence of its enzymatic activity, is a major etiologic factor for atopic dry skin symptoms via an unknown mechanism.
Assuntos
Ceramidase Ácida , Ceramidas , Dermatite Atópica , Epiderme , Camundongos Transgênicos , Animais , Dermatite Atópica/metabolismo , Dermatite Atópica/genética , Dermatite Atópica/patologia , Epiderme/metabolismo , Epiderme/patologia , Ceramidase Ácida/metabolismo , Ceramidase Ácida/genética , Camundongos , Ceramidas/metabolismo , Modelos Animais de Doenças , Pele/metabolismo , Pele/patologiaRESUMO
BACKGROUND: Psoriasis is a common inflammatory skin disease resulting from dysregulation of the IL-23/TH17 immune axis. The prevalence and severity of psoriasis is higher in men than in women, although the underlying reasons for this are unclear. OBJECTIVE: We studied whether estradiol, a female hormone, plays protective roles in imiquimod-induced psoriatic inflammation in mice by regulating neutrophil and macrophage functions. METHODS: Wild-type mice and conditional knockout mice were ovariectomized, supplemented with placebo or estradiol pellets, and an imiquimod-containing cream applied. RESULTS: Mice without endogenous ovarian hormones exhibited exacerbated psoriatic inflammation including increased production of IL-17A and IL-1ß, which was reversed by exogenously added estradiol. The suppressive effect of estradiol on the production of IL-1ß and IL-17A was abolished in mice lacking estrogen receptors in neutrophils and macrophages (Esr1f/fEsr2f/fLysM-Cre+ mice). IL-1ß, which is required for production of IL-17A in the psoriasis model, was mainly produced by neutrophils and inflammatory macrophages. Estradiol suppressed IL-1ß production from neutrophils and macrophages in mice both in vivo and in vitro and from human neutrophils in vitro. CONCLUSION: Our results suggest a novel mechanism for sex-dependent differences in psoriasis clinical phenotypes that may shed new light on the pathology of psoriasis.
Assuntos
Interleucina-17 , Psoríase , Animais , Modelos Animais de Doenças , Estradiol/farmacologia , Estradiol/uso terapêutico , Imiquimode/efeitos adversos , Inflamação/patologia , Interleucina-23 , Macrófagos , Camundongos , Camundongos Knockout , Neutrófilos , Receptores de Estrogênio , PeleRESUMO
COVID-19 is a recently emerged viral infection worldwide. SARS-CoV-2, the causative virus, is believed to have emerged from bat coronaviruses, probably through host conversion. The bat coronavirus which has the highest gene homology to SARS-CoV-2 specifically infects deep forest bats in China whose habitat extends through the Middle East to Southern Europe. Host conversion might have occurred due to the deforestation by humans exposing wild bats to the environment they had never encountered before. SARS-CoV-2 infects cells through two mechanisms: through its receptor ACE2 with the help of enzyme TMPRSS and through membrane fusion with the help of elastases in the inflammatory condition. Obesity, hypertension, diabetes mellitus, and pulmonary diseases cause poor prognosis of COVID-19. Aging is another factor promoting poor prognosis. These diseases and aging cause low-level and persistent inflammation in humans, which can promote poor prognosis of COVID-19. Psoriasis and atopic dermatitis are the major inflammatory skin diseases. These inflammatory skin conditions, however, do not seem to cause poor prognosis for COVID-19 based on the epidemiological data accumulated so far. These mechanisms need to be elucidated.
Assuntos
COVID-19 , Quirópteros , Animais , Humanos , SARS-CoV-2 , Enzima de Conversão de Angiotensina 2 , InflamaçãoRESUMO
The production of melanin pigments by melanocytes and their quantity, quality, and distribution play a decisive role in determining human skin, eye, and hair color, and protect the skin from adverse effects of ultraviolet radiation (UVR) and oxidative stress from various environmental pollutants. Melanocytes reside in the basal layer of the interfollicular epidermis and are compensated by melanocyte stem cells in the follicular bulge area. Various stimuli such as eczema, microbial infection, ultraviolet light exposure, mechanical injury, and aging provoke skin inflammation. These acute or chronic inflammatory responses cause inflammatory cytokine production from epidermal keratinocytes as well as dermal fibroblasts and other cells, which in turn stimulate melanocytes, often resulting in skin pigmentation. It is confirmed by some recent studies that several interleukins (ILs) and other inflammatory mediators modulate the proliferation and differentiation of human epidermal melanocytes and also promote or inhibit expression of melanogenesis-related gene expression directly or indirectly, thereby participating in regulation of skin pigmentation. Understanding of mechanisms of skin pigmentation due to inflammation helps to elucidate the relationship between inflammation and skin pigmentation regulation and can guide development of new therapeutic pathways for treating pigmented dermatosis. This review covers the mechanistic aspects of skin pigmentation caused by inflammation.
Assuntos
Envelhecimento/genética , Inflamação/genética , Melaninas/genética , Pigmentação da Pele/genética , Envelhecimento/efeitos da radiação , Diferenciação Celular/efeitos da radiação , Humanos , Inflamação/patologia , Queratinócitos/efeitos da radiação , Melanócitos/metabolismo , Melanócitos/efeitos da radiação , Pele/patologia , Pele/efeitos da radiação , Pigmentação da Pele/efeitos da radiação , Raios Ultravioleta/efeitos adversosRESUMO
Skin is the largest and most complex organ in the human body comprised of multiple layers with different types of cells. Different kinds of environmental stressors, for example, ultraviolet radiation (UVR), temperature, air pollutants, smoking, and diet, accelerate skin aging by stimulating inflammatory molecules. Skin aging caused by UVR is characterized by loss of elasticity, fine lines, wrinkles, reduced epidermal and dermal components, increased epidermal permeability, delayed wound healing, and approximately 90% of skin aging. These external factors can cause aging through reactive oxygen species (ROS)-mediated inflammation, as well as aged skin is a source of circulatory inflammatory molecules which accelerate skin aging and cause aging-related diseases. This review article focuses on the inflammatory pathways associated with UVR-mediated skin aging.
Assuntos
Inflamação/genética , Transdução de Sinais/efeitos da radiação , Envelhecimento da Pele/genética , Pele/efeitos da radiação , Antioxidantes/uso terapêutico , Elasticidade/efeitos dos fármacos , Humanos , Inflamação/patologia , Inflamação/prevenção & controle , Espécies Reativas de Oxigênio/metabolismo , Pele/metabolismo , Pele/patologia , Envelhecimento da Pele/patologia , Envelhecimento da Pele/efeitos da radiação , Raios Ultravioleta/efeitos adversosRESUMO
Maintenance of retinal ganglion cells (RGCs) activity is relied on axonal transport conveying materials required for their survival such as neurotrophic factors. Kinesin-1 undergoes anterograde transport in axons, and Alcadein α (Alcα; also called calsyntenin-1) is a major cargo adaptor protein that can drive kinesin-1 to transport vesicles containing Alcα. The long-term effects of Alcα-deficiency on retinal morphology and survival of RGCs during postnatal development were examined in Alcα knockout mice. At 1.5, 3, 6, and 15 months postnatal, the number of retrogradely labeled RGCs was determined in flat-mounted retinas of Alcα-deficient and wild-type mice. Retinal damage was assessed histologically by determining the retinal thickness. Intraocular pressure (IOP) was measured with a Tonolab tonometer. At 1.5 months postnatal, the number of retrogradely labeled RGCs was not different between wild-type and Alcα-deficient mice. However, at 3, 6, and 15 months postnatal, the number of RGCs was significantly lower in Alcα deficient mice than those of wild-type mice (143 ± 41.1 cells/mm2 vs. 208 ± 28.4 cells/mm2, respectively, at 3 months; P < 0.01). No differences were seen in retinal thickness or IOP between the two types of mice at any postnatal age. Alcα-deficient mice showed spontaneous loss of RGCs but no elevation in IOP. These mice mimic normal-tension glaucoma and will be useful for investigating the mechanism of neurodegeneration in this disorder and for developing treatments for RGC loss that does not involve changes in IOP.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Axônios/metabolismo , Retina/metabolismo , Células Ganglionares da Retina/metabolismo , Células Ganglionares da Retina/patologia , Animais , Transporte Axonal/fisiologia , Axônios/patologia , Modelos Animais de Doenças , Pressão Intraocular/fisiologia , Cinesinas/deficiência , Cinesinas/metabolismo , Glaucoma de Baixa Tensão/metabolismo , Camundongos Knockout , Vesículas Transportadoras/metabolismoRESUMO
MDGA1 (MAM domain-containing glycosylphosphatidylinositol anchor) has recently been linked to schizophrenia and bipolar disorder. Dysregulation of dopamine (DA) and serotonin (5-HT) systems has long been associated with schizophrenia and other neuropsychiatric disorders. Here, we measured prepulse inhibition (PPI) of the startle response and ex vivo tissue content of monoamines and their metabolites in the frontal cortex, striatum and hippocampus of Mdga1 homozygous (Mdga1-KO), Mdga1 heterozygous (Mdga1-HT) and wild-type (WT) male mice. We found that Mdga1-KO mice exhibited statistically significant impairment of PPI, and had higher levels of homovanillic acid in all three brain regions studied compared with Mdga1-HT and WT mice (P < 0.05), while levels of norepinephrine, DA and its metabolites 3,4-dihydroxyphenylacetic acid and 3-methoxytyramine remained unchanged. Mdga1-KO mice also had a lower 5-hydroxyindoleacetic acid level in the striatum (P < 0.05) compared with WT mice. 5-HT levels remained unchanged with the exception of a significant increase in the level in the cortex. These data are the first evidence suggesting that MDGA1 deficiency leads to a pronounced deficit in PPI and plays an important role in perturbation of DA and 5-HT metabolism in mouse brain; such changes may contribute to a range of neuropsychiatric disorders.