RESUMO
Emerging evidence suggests that dysregulation of neuroinflammation, particularly that orchestrated by microglia, plays a significant role in the pathogenesis of Alzheimer's disease (AD). Danger signals including dead neurons, dystrophic axons, phosphorylated tau, and amyloid plaques alter the functional phenotype of microglia from a homeostatic (M0) to a neurodegenerative or disease-associated phenotype, which in turn drives neuroinflammation and promotes disease. Thus, therapies that target microglia activation constitute a unique approach for treating AD. Here, we report that nasally administered anti-CD3 monoclonal antibody in the 3xTg AD mouse model reduced microglial activation and improved cognition independent of amyloid beta deposition. In addition, gene expression analysis demonstrated decreased oxidative stress, increased axogenesis and synaptic organization, and metabolic changes in the hippocampus and cortex of nasal anti-CD3 treated animals. The beneficial effect of nasal anti-CD3 was associated with the accumulation of T cells in the brain where they were in close contact with microglial cells. Taken together, our findings identify nasal anti-CD3 as a unique form of immunotherapy to treat Alzheimer's disease independent of amyloid beta targeting.
Assuntos
Doença de Alzheimer , Animais , Camundongos , Administração Intranasal , Peptídeos beta-Amiloides , Doenças Neuroinflamatórias , Anticorpos Monoclonais , Modelos Animais de DoençasRESUMO
Intestinal γδ T cells play an important role in shaping the gut microbiota, which is critical not only for maintaining intestinal homeostasis but also for controlling brain function and behavior. Here, we found that mice deficient for γδ T cells (γδ-/-) developed an abnormal pattern of repetitive/compulsive (R/C) behavior, which was dependent on the gut microbiota. Colonization of WT mice with γδ-/- microbiota induced R/C behavior whereas colonization of γδ-/- mice with WT microbiota abolished the R/C behavior. Moreover, γδ-/- mice had elevated levels of the microbial metabolite 3-phenylpropanoic acid in their cecum, which is a precursor to hippurate (HIP), a metabolite we found to be elevated in the CSF. HIP reaches the striatum and activates dopamine type 1 (D1R)-expressing neurons, leading to R/C behavior. Altogether, these data suggest that intestinal γδ T cells shape the gut microbiota and their metabolites and prevent dysfunctions of the striatum associated with behavior modulation.
Assuntos
Microbioma Gastrointestinal , Hipuratos , Linfócitos T , Animais , Camundongos , Corpo Estriado , Neurônios , Comportamento CompulsivoRESUMO
BACKGROUND: The precise mechanism involved in the acquisition of the IL-17+ profile of γδT cells, the ligands responsible for this change, and whether this default is acquired during intrathymic maturation need to be elucidated. OBJECTIVE: This study aimed to evaluate whether IL-17-producing γδT cells are present in the airways of tolerant offspring from allergen-sensitized mothers and the possible implication of maternal IgG in the generation of these cells. METHODS: Female mice were immunized or not, and the allergic response, frequency of γδT cell subsets and cytokine production of the offspring were analysed by flow cytometry. The effects of passive in vivo transfer of purified IgG were investigated in offspring. A translational approach was employed to analyse γδT cells in the thymus and PBMCs from humans. RESULTS: Maternal immunization reduced the frequency of spontaneous IL-17-producing γδT cells in the thymus, spleen and lung of offspring. This effect was mimicked by the in vivo treatment of females with purified IgG. IgG directly interacted with γδT cell membranes. The modulatory effect of human IgG on human infant intrathymic and adult peripheral γδT cells showed similarities to murine γδT cells, which is rarely reported in the literature. CONCLUSIONS & CLINICAL RELEVANCE: Together, our results reveal that IgG from potentially tolerant atopic mothers can influence offspring thymic IL-17-producing γδT cell maturation. Furthermore, we suggest that IgG is an unprecedented modulatory factor of murine and human γδT cells. These observations may support the future development of IgG-based immunoregulatory therapeutic strategies.
Assuntos
Hipersensibilidade/imunologia , Imunoglobulina G/imunologia , Interleucina-17/imunologia , Troca Materno-Fetal/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Linfócitos T/imunologia , Timo/imunologia , Animais , Feminino , Humanos , Hipersensibilidade/genética , Interleucina-17/genética , Troca Materno-Fetal/genética , Camundongos , Camundongos Knockout , Gravidez , Receptores de Antígenos de Linfócitos T gama-delta/genética , Linfócitos T/patologia , Timo/patologiaRESUMO
The associations between human concussions and subsequent sequelae of chronic neuropsychiatric and cardiovascular diseases such as hypertension have been reported; however, little is known about the underlying biological processes. We hypothesized that dietary changes, including a high-salt diet, disrupt the bidirectional gut-brain axis, resulting in worsening neuroinflammation and emergence of cardiovascular and behavioural phenotypes in the chronic period after repetitive closed head injury in adolescent mice. Adolescent mice were subjected to three daily closed head injuries, recovered for 12 weeks and then maintained on a high-salt diet or a normal diet for an additional 12 weeks. Experimental endpoints were haemodynamics, behaviour, microglial gene expression (bulk RNA sequencing), brain inflammation (brain tissue quantitative PCR) and microbiome diversity (16S RNA sequencing). High-salt diet did not affect systemic blood pressure or heart rate in sham or injured mice. High-salt diet increased anxiety-like behaviour in injured mice compared to sham mice fed with high-salt diet and injured mice fed with normal diet. Increased anxiety in injured mice that received a high-salt diet was associated with microgliosis and a proinflammatory microglial transcriptomic signature, including upregulation in interferon-gamma, interferon-beta and oxidative stress-related pathways. Accordingly, we found upregulation of tumour necrosis factor-alpha and interferon-gamma mRNA in the brain tissue of high salt diet-fed injured mice. High-salt diet had a larger effect on the gut microbiome composition than repetitive closed head injury. Increases in gut microbes in the families Lachnospiraceae, Erysipelotrichaceae and Clostridiaceae were positively correlated with anxiety-like behaviours. In contrast, Muribaculaceae, Acholeplasmataceae and Lactobacillaceae were negatively correlated with anxiety in injured mice that received a high-salt diet, a time-dependent effect. The findings suggest that high-salt diet, administered after a recovery period, may affect neurologic outcomes following mild repetitive head injury, including the development of anxiety. This effect was linked to microbiome dysregulation and an exacerbation of microglial inflammation, which may be physiological targets to prevent behavioural sequelae in the chronic period after mild repetitive head injury. The data suggest an important contribution of diet in determining long-term outcomes after mild repetitive head injury.
RESUMO
Dietary proteins are taken up by intestinal dendritic cells (DCs), cleaved into peptides, loaded to major histocompatibility complexes, and presented to T cells to generate an immune response. Amino acid (AA)-diets do not have the same effects because AAs cannot bind to major histocompatibility complex to activate T cells. Here, we show that impairment in regulatory T cell generation and loss of tolerance in mice fed a diet lacking whole protein is associated with major transcriptional changes in intestinal DCs including downregulation of genes related to DC maturation, activation and decreased gene expression of immune checkpoint molecules. Moreover, the AA-diet had a profound effect on microbiome composition, including an increase in Akkermansia muciniphilia and Oscillibacter and a decrease in Lactococcus lactis and Bifidobacterium. Although microbiome transfer experiments showed that AA-driven microbiome modulates intestinal DC gene expression, most of the unique transcriptional change in DC was linked to the absence of whole protein in the diet. Our findings highlight the importance of dietary proteins for intestinal DC function and mucosal tolerance.
RESUMO
BACKGROUND: Gamma-delta (γδ) T cells are a major cell population in the intestinal mucosa and are key mediators of mucosal tolerance and microbiota composition. Little is known about the mechanisms by which intestinal γδ T cells interact with the gut microbiota to maintain tolerance. RESULTS: We found that antibiotic treatment impaired oral tolerance and depleted intestinal γδ T cells, suggesting that the gut microbiota is necessary to maintain γδ T cells. We also found that mice deficient for γδ T cells (γδ-/-) had an altered microbiota composition that led to small intestine (SI) immune dysregulation and impaired tolerance. Accordingly, colonizing WT mice with γδ-/- microbiota resulted in SI immune dysregulation and loss of tolerance whereas colonizing γδ-/- mice with WT microbiota normalized mucosal immune responses and restored mucosal tolerance. Moreover, we found that SI γδ T cells shaped the gut microbiota and regulated intestinal homeostasis by secreting the fecal micro-RNA let-7f. Importantly, oral administration of let-7f to γδ-/- mice rescued mucosal tolerance by promoting the growth of the γδ-/--microbiota-depleted microbe Ruminococcus gnavus. CONCLUSIONS: Taken together, we demonstrate that γδ T cell-selected microbiota is necessary and sufficient to promote mucosal tolerance, is mediated in part by γδ T cell secretion of fecal micro-RNAs, and is mechanistically linked to restoration of mucosal immune responses. Video Abstract.
Assuntos
MicroRNAs , Microbiota , Camundongos , Animais , Linfócitos T , Receptores de Antígenos de Linfócitos T gama-delta/genética , Intestinos , Mucosa Intestinal , Imunidade nas MucosasRESUMO
Physicochemical characterization and antinociceptive and anti-inflammatory activities of atranorin (AT) extracted from Cladina kalbii Ahti in formalin- and capsaicin-induced orofacial pain and anti-inflammatory tests in rodents were studied. Physicochemical characterization showed that AT has the general formula C19H18O8. Male Swiss mice were pretreated with AT (100, 200, and 400 mg/kg, i.p.), morphine (3 mg/kg, i.p.), or vehicle (0.9% saline with two drops of 0.2% Tween 80) before formalin (20 microl, 2%) or capsaicin (20 microl, 2.5 microg) were injected into the right vibrissa. Our results showed that i.p. treatment with AT displayed marked inhibitory effects in different orofacial pain tests in mice. AT (400 mg/kg, i.p.) was effective in reducing the nociceptive face-rubbing behavioural response in both phases of the formalin test, which was also naloxone-sensitive. Additionally, AT produced a significant antinociceptive effect at all doses in the capsaicin test. Such results were unlikely to be provoked by motor abnormality, since AT-treated mice exhibited no performance alteration on the rota rod apparatus. AT exhibited significant anti-inflammatory activity in the acute model of inflammation (leukocyte migration to the peritoneal cavity), carrageenan- and arachidonic acid-induced hind paw edema in rats. Additionally, AT exhibited a dose-dependent antioxidant activity in vitro, as assessed by total radical-trapping antioxidant parameter and total antioxidant reactivity assays. All these findings suggest that AT might represent an important tool for the management of orofacial pain and/or inflammatory disorders.
Assuntos
Hidroxibenzoatos/farmacologia , Medição da Dor/efeitos dos fármacos , Dor/tratamento farmacológico , Alérgenos/farmacologia , Animais , Carragenina , Edema/induzido quimicamente , Edema/tratamento farmacológico , Dor Facial/induzido quimicamente , Dor Facial/tratamento farmacológico , Hidroxibenzoatos/química , Hidroxibenzoatos/uso terapêutico , Hipnóticos e Sedativos/farmacologia , Masculino , Camundongos , Morfina/farmacologia , Morfina/uso terapêutico , Fármacos Neuromusculares Despolarizantes/farmacologia , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Teste de Desempenho do Rota-RodRESUMO
INTRODUCTION: Our group recently demonstrated that IgG modulates αßT cell cytokine production during the maturation process in the human thymus. The effects of this modulation are IgG repertoire dependent and can exert a systemic and long-term impact. OBJECTIVE: To investigate whether IgG from atopic dermatitis (AD) patients can modulate cytokine production of infant intrathymic TCD4 and TCD8 cells in vitro. METHODS: Thymic tissues were obtained from newborn children from nonatopic mothers, and thymocytes were cultured for 6 days with purified IgG from AD patients or with intravenous immunoglobulin (IVIG) or mock conditions as controls. Cells were gated as double positive T cells (TDP- CD4+ CD8+ ), TCD4 cells (CD4+ CD8- ), or TCD8 cells (CD4- CD8+ ), and intracellular levels of IL-17A, IFN-γ, TNF-α, IL-4, IL-10, and TGF-ß were evaluated by flow cytometry. RESULTS: Compared to mock and IVIG culture conditions, IgG of AD individuals induced in vitro intracellular production of IL-17 and IL-10 by intrathymic TDP, TCD4, and TCD8 cells of infants. TGF-ß was also detected at a higher frequency in response to AD IgG in TDP and TCD8 cells compared to mock and IVIG cultured conditions. An opposite effect was detected upon IFN-γ production in TCD4 cells, such that AD IgG reduced IFN-γ production compared to production under mock conditions but not under IVIG conditions. CONCLUSION: IgG of AD patients can stimulate cytokine production in infant thymocytes and thus resembles the peripheral profile observed in adults. These findings suggest a novel mechanism that can contribute to AD pathogenesis.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Citocinas/biossíntese , Imunoglobulina G/farmacologia , Biossíntese de Proteínas/efeitos dos fármacos , Adulto , Células Cultivadas , Dermatite Atópica/sangue , Humanos , Imunoglobulina G/sangue , Imunoglobulinas Intravenosas/farmacologia , Recém-Nascido , Interferon gama/biossíntese , Interleucina-10/biossíntese , Interleucina-17/biossíntese , Interleucina-4/biossíntese , Timócitos , Timo/citologia , Fator de Crescimento Transformador beta/biossíntese , Fator de Necrose Tumoral alfa/biossínteseRESUMO
OBJECTIVE: The aim of the present study was to assess histologically the effect of low-level laser thrapy (LLLT) (lambda 830 nm) on the healing of bone defects associated with autologous bone graft. BACKGROUND DATA: LLLT has been used on the modulation of bone healing because of the photo-physical and photochemical properties of some wavelengths. The use of correct and appropriate parameters has been shown to be effective in the promotion of a positive biomodulative effect on the healing bone. METHODS: Sixty male Wistar rats were divided into four groups: G1 (control), G2 (LLLT on the surgical bed), G3 (LLLT on the graft), and G4 (LLLT on both the graft and the surgical bed). The dose per session was 10 J/cm(2), and it was applied to the surgical bed (G2/G4) and on the bone graft (G3/G4). LLLT was carried out every other day for 15 days (lambda 830 nm, phi = 0.5 cm(2), 50 Mw, 10 J/cm(2)). The dose was fractioned in four points. The animals were sacrificed 15, 21, and 30 days after surgery; specimens were taken and routinely processed (wax, cut, and stain with H&E and Sirius red stains). Light microscopic analysis was performed by a pathologist. RESULTS: In the groups in which the LLLT was used trans-operatively on the surgical bed (G2/G4), bone remodeling was both quantitatively and qualitatively more evident when compared to subjects of groups G1 and G3. CONCLUSION: The present study indicates that the use of LLLT trans-operatively resulted in a positive biomodulative effect on the healing of bone defects associated with autologous bone grafts.
Assuntos
Remodelação Óssea/efeitos da radiação , Fêmur/efeitos da radiação , Terapia com Luz de Baixa Intensidade , Animais , Transplante Ósseo , Fêmur/transplante , Masculino , Ratos , Ratos Wistar , Transplante AutólogoRESUMO
OBJECTIVE: This study aimed to describe, through morphologic and cytochemical analysis, the healing process of wounds submitted (or not) to laser therapy (lambda685 nm) or polarized light (lambda400-2000 nm). BACKGROUND DATA: There are many reports on different effects of several types of phototherapies on the treatment of distinct conditions, amongst them, on wound healing. Laser therapy and the use of polarized light are still controversial despite successive reports on their positive effects on several biological processes. METHODS: Thirty male Wistar rats, approximately 4 months old, were used, and standardized excisional wounds were created on their dorsum. The wounds were irradiated in four equidistant points with laser light or illuminated with polarized light, both with doses of 20 or 40 J/cm2. Group 1 acted as untreated controls. Animals were irradiated every 48 h during 7 days, starting immediately after surgery, and were humanely killed on the 8th post-operative day. Specimens were taken and routinely processed and stained with H&E, and for descriptive analysis of myofibroblasts and collagen fibers, the specimens were imunnomarked by smooth muscle alpha-actin and picrosirius stain. RESULTS: Control specimens showed the presence of ulceration, hyperemia, discrete edema, intense, and diffuse inflammation, collagen deposition was irregular, and myofibroblasts were seen parallel to the wound margins. Wounds treated by laser therapy with a dose of 20 J/cm2 showed mild hyperemia, inflammation varied from moderate to intense, the number of fibroblasts was large, and the distribution of collagen fibers was more regular. Increasing the dose to 40 J/cm2 evidenced exuberant neovascularization, severe hyperemia, moderate to severe inflammation, large collagen deposition, and fewer myofibroblasts. On subjects illuminated with polarized light with a dose of 20 J/cm2, mild to moderate hyperemia was detectable, and collagen matrix was expressive and unevenly distributed; a larger number of myofibroblasts was present and no re-epithelialization was seen. Increasing the dose resulted in mild to moderate hyperemia, no re-epithelialization was seen, edema was discrete, and inflammation was moderate. CONCLUSION: The use of 685-nm laser light or polarized light with a dose of 20 J/cm2 resulted in increased collagen deposition and better organization on healing wounds, and the number of myofibroblast was increased when polarized light is used.
Assuntos
Lasers , Terapia com Luz de Baixa Intensidade/métodos , Cicatrização/fisiologia , Ferimentos e Lesões/patologia , Ferimentos e Lesões/radioterapia , Animais , Biópsia por Agulha , Modelos Animais de Doenças , Imuno-Histoquímica , Masculino , Fotomicrografia , Probabilidade , Distribuição Aleatória , Ratos , Ratos Wistar , Valores de Referência , Sensibilidade e EspecificidadeRESUMO
CONTEXT: Trauma has been an important public health problem worldwide. Facial injuries are among the most common types of trauma treated at emergency departments, associated or not with injuries in other anatomic sites. The patterns of facial fractures are usually affected by geography and socioeconomic conditions. AIM: To investigate the prevalence of facial fractures in Lages, state of Santa Catarina, southern Brazil, from September 2003 to August 2008. SETTINGS AND DESIGN: Cross-sectional, retrospective, epidemiological study. MATERIALS AND METHODS: Data on patients' gender, age, etiological agent, and facial region affected by fracture were collected from the charts of patients treated with facial fractures. STATISTICAL ANALYSIS USED: Qualitative variables were expressed as absolute and relative frequencies, and quantitative variables as means and standard deviation. The Chi-square test was used to evaluate the association between gender, traffic accidents and facial region affected. The association between etiological agents and facial region affected was assessed using the chi-square test and the adjusted residuals analysis. RESULTS: 492 patients presented with oral and maxillofacial trauma, with 988 facial fractures; 80.9% of the patients were men, and the most frequent age group was 21-30 years (29.5%). The most frequent causes of fractures were: Traffic accidents in 27.9%, physical assault in 14.9%, and bicycle falls in 10.5%; several other causes scored below 10%. CONCLUSION: Regular publication of epidemiological data is extremely important for the implementation of prevention campaigns and for an increased awareness of the etiology of fractures affecting the face and other anatomic sites.
Assuntos
Ossos Faciais/lesões , Fraturas Cranianas/epidemiologia , Acidentes de Trânsito/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Ciclismo/lesões , Brasil/epidemiologia , Criança , Estudos Transversais , Estudos Epidemiológicos , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Fraturas Mandibulares/epidemiologia , Fraturas Maxilares/epidemiologia , Pessoa de Meia-Idade , Osso Nasal/lesões , Traumatismos Ocupacionais/epidemiologia , Características de Residência/estatística & dados numéricos , Estudos Retrospectivos , Estações do Ano , Fatores Sexuais , Violência/estatística & dados numéricos , Adulto Jovem , Fraturas Zigomáticas/epidemiologiaRESUMO
The use of multi-component femoral implants to replace the femur head and re-establish bone motion has been widespread since the 70s. Frequently these implants have spherical metallic heads made of, for example, 316-L stainless steel or Cr-Co alloys, which allow rotational motion towards a polymeric component (UHMWPE). One of the major causes of implant rejection is the generation of UHMWPE debris on the surface between the implant head and the polymeric component. The gamma ray sterilization of implants and the periodical X-ray medical control could contribute to premature degradation of the polymeric surface, resulting in increased wear and shortened lifetime of the implant. In this work we study the degradation degree of the polymeric UHMWPE component as function of the X-ray dose. The elasto-plastic deformation and recovery were carried out by means of a nanohardness tester equipment and the polymer degradation was measured using a fast Fourier transform infra-red (FT-IR) equipment. The results show the compromise among the irradiation doses, the surface oxidation and the mechanical properties of the samples.
Assuntos
Materiais Biocompatíveis/química , Materiais Biocompatíveis/efeitos da radiação , Polietilenos/química , Polietilenos/efeitos da radiação , Radiografia , Raios X , Força Compressiva/efeitos da radiação , Relação Dose-Resposta à Radiação , Elasticidade/efeitos da radiação , Dureza/efeitos da radiação , Teste de Materiais , Doses de Radiação , Propriedades de Superfície/efeitos da radiaçãoRESUMO
OBJECTIVE: The aim of this study was to evaluate morphometrically the amount of newly formed bone after GaAlAs laser irradiation of surgical wounds created in the femur of rats. BACKGROUND DATA: Low-level laser therapy (LLLT) has been used in several medical specialties because of its biomodulatory effects on different biological tissues. However, LLLT is still controversial because of contradictory reports. This is a direct result of the different methodologies used in these works. MATERIALS AND METHODS: In this study, 40 Wistar rats were divided into four groups of 10 animals each: group A (12 sessions, 4.8 J/cm2 per session, observation time of 28 days); group C (three sessions, 4.8 J/cm2 per session, observation time of 7 days). Groups B and D acted as nonirradiated controls. The specimens were routinely processed to wax and cut at 6-microm thickness and stained with H&E. For computerized morphometry, Imagelab software was used. RESULTS: Computerized morphometry showed a significant difference between the areas of mineralized bone in groups C and D (p = 0.017). There was no difference between groups A and B (28 days; p = 0.383). CONCLUSION: It is concluded that, under this experimental condition, LLLT increased bone repair at early bone healing.